Sudo Stable Release

Current Stable Release

The current stable release of sudo is 1.8.7.

For full details see the ChangeLog file or view the commit logs via mercurial.

Major changes between version 1.8.7 and 1.8.6p8:

  • The non-Unix group plugin is now supported when sudoers data is stored in LDAP.

  • Sudo now uses a workaround for a locale bug on Solaris 11.0 that prevents setuid programs like sudo from fully using locales.

  • User messages are now always displayed in the user's locale, even when the same message is being logged or mailed in a different locale.

  • Log files created by sudo now explicitly have the group set to group ID 0 rather than relying on BSD group semantics (which may not be the default).

  • A new exec_background sudoers option can be used to initially run the command without read access to the terminal when running a command in a pseudo-tty. If the command tries to read from the terminal it will be stopped by the kernel (via SIGTTIN or SIGTTOU) and sudo will immediately restart it as the forground process (if possible). This allows sudo to only pass terminal input to the program if the program actually is expecting it. Unfortunately, a few poorly-behaved programs (like "su" on most Linux systems) do not handle SIGTTIN and SIGTTOU properly.

  • Sudo now uses an efficient group query to get all the groups for a user instead of iterating over every online short-term loan record in the group database on HP-UX and Solaris.

  • Sudo now produces better error messages when there is an error in the sudo.conf file.

  • Two new settings have been added to sudo.conf to give the admin better control of how group database queries are performed. The group_source specifies how the group list for a user will be determined. Legal values are static (use the kernel groups list), dynamic (perform a group database query) and adaptive (only perform a group database query if the kernel list is full). The max_groups setting specifies the maximum number of groups a user may belong to when performing a group database query.

  • The sudo.conf file now supports line continuation by using a backslash as the last character on the line.

  • There is now a standalone sudo.conf manual page.

  • Sudo now stores its libexec files in a sudo subdirectory instead of in libexec itself. For backwards compatibility, if the plugin is not found in the default plugin directory, sudo will check the parent directory if the default directory ends in /sudo.

  • The sudoers I/O logging plugin now logs the terminal size.

  • A new sudoers option maxseq can be used to limit the number of I/O log entries that are stored.

  • The system_group and group_file sudoers group provider plugins are now installed by default.

  • The list output (sudo -l) output from the sudoers plugin is now less ambiguous when an entry includes different runas users. The long list output (sudo -ll) for file-based sudoers is now more consistent with the format of LDAP-based sudoers.

  • A uid may now be used in the sudoRunAsUser attributes for LDAP sudoers.

  • Minor plugin API change: the close and version functions are now optional. If the policy plugin does not provide a close function and the command is not being run in a new pseudo-tty, sudo may now execute the command directly instead of in a child process.

  • A new sudoers option pam_session can be used to disable sudo's PAM session support.

  • On HP-UX systems, sudo will now use the pstat() function to determine the tty instead of ttyname().

  • Turkish translation for sudo and sudoers from

  • Dutch translation for sudo and sudoers from

  • Tivoli Directory Server client libraries may now be used with HP-UX where libibmldap has a hidden dependency on libCsup.

  • The sudoers plugin will now ignore invalid domain names when checking netgroup membership. Most Linux systems use the string "(none)" for the NIS-style domain name instead of an empty string.

  • New support for specifying a SHA-2 digest along with the command in sudoers. Supported hash types are sha224, sha256, sha384 and sha512. See the description of Digest_Spec in the sudoers manual or the description of sudoCommand in the sudoers.ldap manual for details.

  • The paths to ldap.conf and ldap.secret may now be specified as arguments to the sudoers plugin in the sudo.conf file.

  • Fixed potential false positives in visudo's alias cycle detection.

  • Fixed a problem where the time stamp file was being treated as out of date on Linux systems where the change time on the pseudo-tty device node can change after it is allocated.

  • Sudo now only builds Position Independent Executables (PIE) by default on Linux systems and verifies that a trivial test program builds and runs.

  • On Solaris 11.1 and higher, sudo binaries will now have the ASLR tag enabled if supported by the linker.

Major changes between version 1.8.6p8 and 1.8.6p7:

  • Terminal detection now works properly on 64-bit AIX kernels. This was broken by the removal of the ttyname() fallback in Sudo 1.8.6p6. Sudo is now able to map an AIX 64-bit device number to the corresponding device file in /dev.

  • Sudo now checks for crypt() returning NULL when performing passwd-based authentication.

Major changes between version 1.8.6p7 and 1.8.6p6:

  • A time stamp file with the date set to the epoch by sudo -k is now completely ignored regardless of what the local clock is set to. Previously, if the local clock was set to a value between the epoch and the time stamp timeout value, a time stamp reset by sudo -k would be considered current.
    This is a potential security issue.

  • The tty-specific time stamp file now includes the session ID of the sudo process that created it. If a process with the same tty but a different session ID runs sudo, the user will now be prompted for a password (assuming authentication is required for the command).
    This is a potential security issue.

Major changes between version 1.8.6p6 and 1.8.6p5:

  • On systems where the controlling tty can be determined via /proc or sysctl(), sudo will no longer fall back to using ttyname() if the process has no controlling tty. This prevents sudo from using a non-controlling tty for logging and time stamp purposes.
    This is a potential security issue.

Major changes between version 1.8.6p5 and 1.8.6p4:

  • Fixed a potential crash in visudo's alias cycle detection.

  • Improved performance on Solaris when retrieving the group list for the target user. On systems with a large number of groups where the group database is not local (NIS, LDAP, AD), fetching the group list could take a minute or more.

Major changes between version 1.8.6p4 and 1.8.6p3:

  • The -fstack-protector is now used when linking visudo, sudoreplay and testsudoers.

  • Avoid building PIE binaries on FreeBSD/ia64 as they don't run properly.

  • Fixed a crash in visudo strict mode when an unknown Defaults setting is encountered.

  • Do not inform the user that the command was not permitted by the policy if they do not successfully authenticate. This is a regression introduced in sudo 1.8.6.

  • Allow sudo to be build with sss support without also including ldap support.

  • Fix running commands that need the terminal in the background when I/O logging is enabled. E.g. sudo vi &. When the command is foregrounded, it will now resume properly.

Major changes between version 1.8.6p3 and 1.8.6p2:

  • Fixed post-processing of the man pages on systems with legacy versions of sed.

  • Fixed sudoreplay -l on Linux systems with file systems that set DT_UNKNOWN in the d_type field of struct dirent.

Major changes between version 1.8.6p2 and 1.8.6p1:

  • Fixed suspending a command after it has already been resumed once when I/O logging (or use_pty) is not enabled. This was a regression introduced in version 1.8.6.

Major changes between version 1.8.6p1 and 1.8.6:

  • Fixed the setting of LOGNAME, USER and USERNAME variables in the command's environment when env_reset is enabled (the default). This was a regression introduced in version 1.8.6.

  • Sudo now honors SUCCESS=return in /etc/nsswitch.conf.

Major changes between version 1.8.6 and 1.8.5p3:

  • Sudo is now built with the -fstack-protector flag if the the compiler supports it. Also, the -zrelro linker flag is used if supported. The --disable-hardening configure option can be used to build sudo without stack smashing protection.

  • Sudo is now built as a Position Independent Executable (PIE) if supported by the compiler and linker.

  • If the user is a member of the exempt group in sudoers, they will no longer be prompted for a password even if the -k flag is specified with the command. This makes sudo -k command consistent with the behavior one would get if the user ran sudo -k immediately before running the command.

  • The sudoers file may now be a symbolic link. Previously, sudo would refuse to read sudoers unless it was a regular file.

  • The sudoreplay command can now properly replay sessions where no tty was present.

  • The sudoers plugin now takes advantage of symbol visibility controls when supported by the compiler or linker. As a result, only a small number of symbols are exported which significantly reduces the chances of a conflict with other shared objects.

  • Improved support for the Tivoli Directory Server LDAP client libraries. This includes support for using LDAP over SSL (ldaps) as well as support for the BIND_TIMELIMIT, TLS_KEY and TLS_CIPHERS ldap.conf options. A new ldap.conf option, TLS_KEYPW can be used to specify a password to decrypt the key database.

  • When constructing a time filter for use with LDAP sudoNotBefore and sudoNotAfter attributes, the current time now includes tenths of a second. This fixes a problem with timed entries on Active Directory.

  • If a user fails to authenticate and the command would be rejected by sudoers, it is now logged with command not allowed instead of N incorrect password attempts. Likewise, the mail_no_perms sudoers option now takes precedence over mail_badpass

  • The sudo manuals are now formatted using the mdoc macros. Versions using the legacy man macros are provided for systems that lack mdoc.

  • New support for Solaris privilege sets. This makes it possible to specify fine-grained privileges in the sudoers file on Solaris 10 and above. A Runas_Spec that contains no Runas_Lists can be used to give a user the ability to run a command as themselves but with an expanded privilege set.

  • Fixed a problem with the reboot and shutdown commands on some systems (such as HP-UX and BSD). On these systems, reboot sends all processes (except itself) SIGTERM. When sudo received SIGTERM, it would relay it to the reboot process, thus killing reboot before it had a chance to actually reboot the system.

  • Support for using the System Security Services Daemon (SSSD) as a source of sudoers data.

  • Slovenian translation for sudo and sudoers from

  • Visudo will now warn about unknown Defaults entries that are per-host, per-user, per-runas or per-command.

  • Fixed a race condition that could cause sudo to receive SIGTTOU (and stop) when resuming a shell that was run via sudo when I/O logging (and use_pty) is not enabled.

  • Sending SIGTSTP directly to the sudo process will now suspend the running command when I/O logging (and use_pty) is not enabled.

Major changes between version 1.8.5p3 and 1.8.5p2:

  • Fixed the loading of I/O plugins that conform to a plugin API version older than 1.2.

Major changes between version 1.8.5p2 and 1.8.5p1:

  • Fixed use of the SUDO_ASKPASS environment variable which was broken in Sudo 1.8.5.

  • Fixed a problem reading the sudoers file when the file mode is more restrictive than the expected mode. For example, when the expected sudoers file mode is 0440 but the actual mode is 0400.

Major changes between version 1.8.5p1 and 1.8.5:

  • Fixed a bug that prevented files in an include directory from being evaluated.

Major changes between version 1.8.5 and 1.8.4p5:

  • When "noexec" is enabled, will now be prepended to any existing LD_PRELOAD variable instead of replacing it.

  • The shared library now wraps the execvpe(), exect(), posix_spawn() and posix_spawnp() functions.

  • The user/group/mode checks on sudoers files have been relaxed. As long as the file is owned by the sudoers uid, not world-writable and not writable by a group other than the sudoers gid, the file is considered OK. Note that visudo will still set the mode to the value specified at configure time.

  • It is now possible to specify the sudoers path, uid, gid and file mode as options to the plugin in the sudo.conf file.

  • Croatian, Galician, German, Lithuanian, Swedish and Vietnamese translations from

  • /etc/environment is no longer read directly on Linux systems when PAM is used. Sudo now merges the PAM environment into the user's environment which is typically set by the pam_env module.

  • The initial evironment created when env_reset is in effect now includes the contents of /etc/environment on AIX systems and the "setenv" and "path" entries from /etc/login.conf on BSD systems.

  • The plugin API has been extended in three ways. First, options specified in sudo.conf after the plugin pathname are passed to the plugin's open function. Second, sudo has limited support for hooks that can be used by plugins. Currently, the hooks are limited to environment handling functions. Third, the init_session policy plugin function is passed a pointer to the user environment which can be updated during session setup. The plugin API version has been incremented to version 1.2. See the sudo_plugin manual for more information.

  • The policy plugin's init_session function is now called by the parent sudo process, not the child process that executes the command. This allows the PAM session to be open and closed in the same process, which some PAM modules require.

  • Fixed parsing of "Path askpass" and "Path noexec" in sudo.conf, which was broken in version 1.8.4.

  • On systems with an SVR4-style /proc file system, the /proc/pid/psinfo file is now uses to determine the controlling terminal, if possible. This allows tty-based tickets to work properly even when, e.g. standard input, output and error are redirected to /dev/null.

  • The output of "sudoreplay -l" is now sorted by file name (or sequence number). Previously, entries were displayed in the order in which they were found on the file system.

  • Sudo now behaves properly when I/O logging is enabled and the controlling terminal is revoked (e.g. the running sshd is killed). Previously, sudo may have exited without calling the I/O plugin's close function which can lead to an incomplete I/O log.

  • Sudo can now detect when a user has logged out and back in again on Solaris 11, just like it can on Solaris 10.

  • The built-in zlib included with Sudo has been upgraded to version 1.2.6.

  • Setting the SSL parameter to start_tls in ldap.conf now works properly when using Mozilla-based SDKs that support the ldap_start_tls_s() function.

  • The TLS_CHECKPEER parameter in ldap.conf now works when the Mozilla NSS crypto backend is used with OpenLDAP.

  • A new group provider plugin, system_group, is included which performs group look ups by name using the system groups database. This can be used to restore the pre-1.7.3 sudo group lookup behavior.

Major changes between version 1.8.4p5 and 1.8.4p4:

  • Fixed a potential security issue in the matching of hosts against an IPv4 network specified in sudoers. The flaw may allow a user who is authorized to run commands on hosts belonging to one IPv4 network to run commands on a different host.

Major changes between version 1.8.4p4 and 1.8.4p3:

  • Fixed a bug introduced in Sudo 1.8.4 which prevented sudo -v from working.

Major changes between version 1.8.4p3 and 1.8.4p2:

  • Fixed a crash on FreeBSD when there is no tty present.

  • When visudo is run with the -c (check) option, the sudoers file(s) owner and mode are now also checked unless the -f option was specified.

Major changes between version 1.8.4p2 and 1.8.4p1:

  • Fixed a bug introduced in Sudo 1.8.4 where insufficient space was allocated for group IDs in the LDAP filter.

  • Fixed a bug introduced in Sudo 1.8.4 where the path to sudo.conf was /sudo.conf instead of etc/sudo.conf.

  • Fixed a bug introduced in Sudo 1.8.4 which could cause a hang when I/O logging is enabled and input is from a pipe or file.

Major changes between version 1.8.4p1 and 1.8.4:

  • Fixed a bug introduced in sudo 1.8.4 that broke adding to or deleting from the env_keep, env_check and env_delete lists in sudoers on some platforms.

Major changes between version 1.8.4 and 1.8.3p2:

  • The -D flag in sudo has been replaced with a more general debugging framework that is configured in sudo.conf.

  • Fixed a false positive in visudo strict mode when aliases are in use.

  • Fixed a crash with sudo -i when a runas group was specified without a runas user.

  • The line on which a syntax error is reported in the sudoers file is now more accurate. Previously it was often off by a line.

  • Fixed a bug where stack garbage could be printed at the end of the lecture when the lecture_file option was enabled.

  • make install now honors the LINGUAS environment variable.

  • The #include and #includedir directives in sudoers now support relative paths. If the path is not fully qualified it is expected to be located in the same directory of the sudoers file that is including it.

  • New Serbian and Spanish translations for sudo from

  • LDAP-based sudoers may now access by group ID in addition to group name.

  • visudo will now fix the mode on the sudoers file even if no changes are made unless the -f option is specified.

  • The use_loginclass sudoers option works properly again.

  • On systems that use login.conf, sudo -i now sets environment variables based on login.conf.

  • For LDAP-based sudoers, values in the search expression are now escaped as per RFC 4515.

  • The plugin close function is now properly called when a login session is killed (as opposed to the actual command being killed). This can happen when an ssh session is disconnected or the terminal window is closed.

  • The deprecated "noexec_file" sudoers option is no longer supported.

  • Fixed a race condition when I/O logging is not enabled that could result in tty-generated signals (e.g. control-C) being received by the command twice.

  • If none of the standard input, output or error are connected to a tty device, sudo will now check its parent's standard input, output or error for the tty name on systems with /proc and BSD systems that support the KERN_PROC_PID sysctl. This allows tty-based tickets to work properly even when, e.g. standard input, output and error are redirected to /dev/null.

  • Added the --enable-kerb5-instance configure option to allow people using Kerberos V authentication to specify a custom instance so the principal name can be, e.g. "username/sudo" similar to how ksu uses "username/root".

  • Fixed a bug where a pattern like /usr/* included /usr/bin/ in the results, which would be incorrectly be interpreted as if the sudoers file had specified a directory.

  • visudo -c will now list any include files that were checked in addition to the main sudoers file when everything parses OK.

  • Users that only have read-only access to the sudoers file may now run visudo -c. Previously, write permissions were required even though no writing is down in check-only mode.

  • It is now possible to prevent the disabling of core dumps from within sudo itself by adding a line to the sudo.conf file like Set disable_coredump false.

Major changes between version 1.8.3p2 and 1.8.3p1:

  • Fixed a format string vulnerability when the sudo binary (or a symbolic link to the sudo binary) contains printf format escapes and the -D (debugging) flag is used.

Major changes between version 1.8.3p1 and 1.8.3:

  • Fixed a crash in the monitor process on Solaris when NOPASSWD was specified or when authentication was disabled.

  • Fixed matching of a Runas_Alias in the group section of a Runas_Spec.

Major changes between version 1.8.3 and 1.8.2:

  • Fixed expansion of strftime() escape sequences in the log_dir sudoers setting.

  • Esperanto, Italian and Japanese translations from

  • Sudo will now use PAM by default on AIX 6 and higher.

  • Added --enable-werror configure option for gcc's -Werror flag.

  • Visudo no longer assumes all editors support the +linenumber command line argument. It now uses a whitelist of editors known to support the option.

  • Fixed matching of network addresses when a netmask is specified but the address is not the first one in the CIDR block.

  • The configure script now check whether or not errno.h declares the errno variable. Previously, sudo would always declare errno itself for older systems that don't declare it in errno.h.

  • The NOPASSWD tag is now honored for denied commands too, which matches historic sudo behavior (prior to sudo 1.7.0).

  • Sudo now honors the DEREF setting in ldap.conf which controls how alias dereferencing is done during an LDAP search.

  • A symbol conflict with the pam_ssh_agent_auth PAM module that would cause a crash been resolved.

  • The inability to load a group provider plugin is no longer a fatal error.

  • A potential crash in the utmp handling code has been fixed.

  • Two PAM session issues have been resolved. In previous versions of sudo, the PAM session was opened as one user and closed as another. Additionally, if no authentication was performed, the PAM session would never be closed.

  • Sudo will now work correctly with LDAP-based sudoers using TLS or SSL on Debian systems.

  • The LOGNAME, USER and USERNAME environment variables are preserved correctly again in sudoedit mode.

Major changes between version 1.8.2 and 1.8.1p2:

  • Sudo, visudo, sudoreplay and the sudoers plug-in now have natural language support (NLS). Sudo will use gettext(), if available, to display translated messages. This can be disabled by passing configure the --disable-nls option. All translations are coordinated via The Translation Project, Sudo 1.8.2 includes translations for Basque, Chinese (simplified), Danish, Finish, Polish, Russian and Ukranian.

  • Plug-ins are now loaded with the RTLD_GLOBAL flag instead of RTLD_LOCAL. This fixes missing symbol problems in PAM modules on certain platforms, such as FreeBSD and SuSE Linux Enterprise.

  • I/O logging is now supported for commands run in background mode (using sudo's -b flag).

  • Group ownership of the sudoers file is now only enforced when the file mode on sudoers allows group readability or writability.

  • Visudo now checks the contents of an alias and warns about cycles when the alias is expanded.

  • If the user specifes a group via sudo's -g option that matches the target user's group in the password database, it is now allowed even if no groups are present in the Runas_Spec.

  • The sudo Makefiles now have more complete dependencies which are automatically generated instead of being maintained manually.

  • The use_pty sudoers option is now correctly passed back to the sudo front end. This was missing in previous versions of sudo 1.8 which prevented use_pty from being honored.

  • sudo -i command now works correctly with the bash version 2.0 and higher. Previously, the .bash_profile would not be sourced prior to running the command unless bash was built with NON_INTERACTIVE_LOGIN_SHELLS defined.

  • When matching groups in the sudoers file, sudo will now match based on the name of the group instead of the group ID. This can substantially reduce the number of group lookups for sudoers files that contain a large number of groups.

  • Multi-factor authentication is now supported on AIX.

  • Added support for non-RFC 4517 compliant LDAP servers that require that seconds be present in a timestamp, such as Tivoli Directory Server.

  • If the group vector is to be preserved, the PATH search for the command is now done with the user's original group vector.

  • For LDAP-based sudoers, the runas_default sudoOption now works properly in a sudoRole that contains a sudoCommand.

  • Spaces in command line arguments for sudo -s and sudo -i are now escaped with a backslash when checking the security policy.

Major changes between version 1.8.1p2 and 1.8.1p1:

  • Two-character CIDR-style IPv4 netmasks are now matched correctly in the sudoers file.

  • A build error with MIT Kerberos V has been resolved.

  • A crash on HP-UX in the sudoers plugin when wildcards are present in the sudoers file has been resolved.

  • Sudo now works correctly on Tru64 Unix again.

Major changes between version 1.8.1p1 and 1.8.1:

  • Fixed a problem on AIX where sudo was unable to set the final uid if the PAM module modified the effective uid.

  • A non-existent includedir is now treated the same as an empty directory and not reported as an error.

  • Removed extraneous parens in LDAP filter when sudoers_search_filter is enabled that can cause an LDAP search error.

  • Fixed a make -j problem for make install

Major changes between version 1.8.1 and 1.8.0:

  • A new LDAP setting, sudoers_search_filter, has been added to ldap.conf. This setting can be used to restrict the set of records returned by the LDAP query. Based on changes from Matthew Thomas.

  • White space is now permitted within a User_List when used in conjunction with a per-user Defaults definition.

  • A group ID (%#gid) may now be specified in a User_List or Runas_List. Likewise, for non-Unix groups the syntax is %:#gid.

  • Support for double-quoted words in the sudoers file has been fixed. The change in 1.7.5 for escaping the double quote character caused the double quoting to only be available at the beginning of an entry.

  • The fix for resuming a suspended shell in 1.7.5 caused problems with resuming non-shells on Linux. Sudo will now save the process group ID of the program it is running on suspend and restore it when resuming, which fixes both problems.

  • A bug that could result in corrupted output in "sudo -l" has been fixed.

  • Sudo will now create an entry in the utmp (or utmpx) file when allocating a pseudo-tty (e.g. when logging I/O). The "set_utmp" and "utmp_runas" sudoers file options can be used to control this. Other policy plugins may use the "set_utmp" and "utmp_user" entries in the command_info list.

  • The sudoers policy now stores the TSID field in the logs even when the "iolog_file" sudoers option is defined to a value other than %{sessid}. Previously, the TSID field was only included in the log file when the "iolog_file" option was set to its default value.

  • The sudoreplay utility now supports arbitrary session IDs. Previously, it would only work with the base-36 session IDs that the sudoers plugin uses by default.

  • Sudo now passes "run_shell=true" to the policy plugin in the settings list when sudo's -s command line option is specified. The sudoers policy plugin uses this to implement the "set_home" sudoers option which was missing from sudo 1.8.0.

  • The "noexec" functionality has been moved out of the sudoers policy plugin and into the sudo front-end, which matches the behavior documented in the plugin writer's guide. As a result, the path to the noexec file is now specified in the sudo.conf file instead of the sudoers file.

  • On Solaris 10, the PRIV_PROC_EXEC privilege is now used to implement the "noexec" feature. Previously, this was implemented via the LD_PRELOAD environment variable.

  • The exit values for "sudo -l", "sudo -v" and "sudo -l command" have been fixed in the sudoers policy plugin.

  • The sudoers policy plugin now passes the login class, if any, back to the sudo front-end.

  • The sudoers policy plugin was not being linked with requisite libraries in certain configurations.

  • Sudo now parses command line arguments before loading any plugins. This allows "sudo -V" or "sudo -h" to work even if there is a problem with sudo.conf

  • Plugins are now linked with the static version of libgcc to allow the plugin to run on a system where no shared libgcc is installed, or where it is installed in a different location.

Major changes between version 1.8.0 and 1.7.5:

  • Sudo has been refactored to use a modular framework that can support third-party policy and I/O logging plugins. The default plugin is "sudoers" which provides the traditional sudo functionality. See the sudo_plugin manual for details on the plugin API and the sample in the plugins directory for a simple example.