* Fixed a bug introduced in sudo 1.9.16 that could result in sudo sending `SIGHUP` to all processes on the system in certain rare cases. The bug could manifest if sudo is running a command in a pseudo-terminal, sudo terminates the command due to an internal error, and the user's terminal is revoked. [GitHub issue #458](https://github.com/sudo-project/sudo/issues/458). * Fixed a bug introduced in sudo 1.9.12 that caused sudo to abort when the _intercept_ and _intercept_verify_ options are enabled in sudoers and either the command line arguments or the environment contains a string larger than the page size (usually 4096). This only Linux affects systems that support the `ptrace_readv_string()` function. [GitHub issue #453](https://github.com/sudo-project/sudo/issues/453). * Fixed a bug in sudo's configure script introduced in sudo 1.9.17 that prevented mdoc-format man pages from being used on systems without the mandoc utility. [Bug #1077](https://bugzilla.sudo.ws/show_bug.cgi?id=1077).

* Sudo now uses the `NODEV` macro consistently. [Bug #1074](https://bugzilla.sudo.ws/show_bug.cgi?id=1074). * Fixed a bug where the _ALL_ command in a sudoers rule would override a previous _NOSETENV_ tag. Command tags are inherited from previous Cmnds in a Cmnd_Spec_List. There is a special case for the _SETENV_ tag with the _ALL_ command, where _SETENV_ is implied if no explicit _SETENV_ or _NOSETENV_ tag is specified. This special case did not take into account that a _NOSETENV_ tag that was inherited should override this behavior. * If sudo is run via ssh without a terminal and a password is required, it now suggest using ssh's `-t` option. * Fixed the display of timeout values in the `sudo -V` output on systems without a C99-compliant `snprintf()` function. * Quieted a number of minor Coverity warnings. * Fixed a problem running sudo from a serial console on Linux when the command is run in a pseudo-terminal (the default). * Fixed a crash in sudo which could occur if there was a fatal error after the user was validated but before the command was actually run. * Fixed a number of man page style warnings. The "lint" make target in the docs directory will now run groff with warnings enabled if it is available. [Bug #1075](https://bugzilla.sudo.ws/show_bug.cgi?id=1075). * The _ignore_dot_ sudoers setting is now on by default. There is now a `--disable-ignore-dot` configure option to disable it. The `--with-ignore-dot` configure option has been deprecated. * Fixed a problem with the _pwfeedback_ option where an initial backspace would reduce the maximum length allowed for the password. [GitHub issue #439](https://github.com/sudo-project/sudo/issues/439). * Fixed minor grammar and spelling problems in the man pages. * Fixed a bug where a user could avoid entering a password for `sudo -l command` if they specified their own user or group name via the `-u` or `-g` options. * Avoid potential password guessing based on timing attacks on the `strcmp()` function on systems without PAM or a `crypt()` function where plaintext passwords are stored in the shadow password file. * Fixed a potential information leak where `sudo -l command` could be used to determine whether an executable exists in a directory that they do not have search access to. * Sudo uses `TCSAFLUSH`, not `TCSADRAIN`, when disabling echo once again. A long time ago sudo changed from using `TCSAFLUSH` to `TCSADRAIN` due to some systems having bugs related to `TCSAFLUSH`. That should no longer be a concern. Using `TCSAFLUSH` ensures that password input that has been received by the kernel, but not yet read by sudo, will be discarded and not echoed. * Added the `SUDO_TTY` environment variable if the user has a terminal. This can be used to find the user's original tty device when sudo runs the command in its own pseudo-terminal. [GitHub issue #447](https://github.com/sudo-project/sudo/issues/447). * New Cantonese translation for sudo.

* Fixed the test for cross-compiling when checking for C99 snprintf(). The changes made to the test in sudo 1.9.16 resulted in a different problem. [GitHub issue #386](https://github.com/sudo-project/sudo/issues/386). * Fixed the date used by the exit record in sudo-format log files. This was a regression introduced in sudo 1.9.16 and only affected file-based logs, not syslog. [GitHub issue #405](https://github.com/sudo-project/sudo/issues/405). * Fixed the root cause of the "unable to find terminal name for device" message when running sudo on AIX when no terminal is present. In sudo 1.9.16 this was turned from a debug message into a warning. [GitHub issue #408](https://github.com/sudo-project/sudo/issues/408). * When a duplicate alias is found in the sudoers file, the warning message now includes the file and line number of the previous definition. * Added support for the `--with-secure-path-value=no` configure option to allow packagers to ship the default sudoers file with the secure path line commented out. * Sudo no longer sends mail when a user runs `sudo -nv` or `sudo -nl`, even if _mail_badpass_ or _mail_always_ are set. Sudo already avoids logging to a file or syslog in this case. [Bug #1072](https://bugzilla.sudo.ws/show_bug.cgi?id=1072).

* Added the _cmddenial_message_ sudoers option to provide additional information to the user when a command is denied by the sudoers policy. The default message is still displayed. * The time stamp used for file-based logs is now more consistent with the time stamp produced by syslog. [GitHub issue #327](https://github.com/sudo-project/sudo/issues/327). * Sudo will now warn the user if it can detect the user's terminal but cannot determine the path to the terminal device. The sudoers time stamp file will now use the terminal device number directly. [GitHub issue #329](https://github.com/sudo-project/sudo/issues/329). * The embedded copy of zlib has been updated to version 1.3.1. * Improved error handling if generating the list of signals and signal names fails at build time. * Fixed a compilation issue on Linux systems without process_vm_readv(). * Fixed cross-compilation with WolfSSL. * Added a __json_compact__ value for the sudoers _log_format_ option which can be used when logging to a file. The existing __json__ value has been aliased to __json_pretty__. In a future release, __json__ will be an alias for __json_compact__. [GitHub issue #357](https://github.com/sudo-project/sudo/issues/357). * A new _pam_silent_ sudoers option has been added which may be negated to avoid suppressing output from PAM authentication modules. [GitHub issue #216](https://github.com/sudo-project/sudo/issues/216). * Fixed several cvtsudoers JSON output problems. GitHub issues [#369](https://github.com/sudo-project/sudo/issues/369), [#370](https://github.com/sudo-project/sudo/issues/370), [#371](https://github.com/sudo-project/sudo/issues/371), [#373](https://github.com/sudo-project/sudo/issues/373), [#381](https://github.com/sudo-project/sudo/issues/381). * When sudo runs a command in a pseudo-terminal and the user's terminal is revoked, the pseudo-terminal's foreground process group will now receive `SIGHUP` before the terminal is revoked. This emulates the behavior of the session leader exiting and is consistent with what happens when, for example, an ssh session is closed. [GitHub issue #367](https://github.com/sudo-project/sudo/issues/367). * Fixed _make test_ with Python 3.12. [GitHub issue #374](https://github.com/sudo-project/sudo/issues/374). * In schema.ActiveDirectory, fixed the quoting in the example command. [GitHub issue #376](https://github.com/sudo-project/sudo/issues/376). * Paths specified via a _Chdir_Spec_ or _Chroot_Spec_ in sudoers may now be double-quoted. * Sudo insults are now included by default, but disabled unless the `--with-insults` configure option is specified or the _insults_ sudoers option is enabled. * The default sudoers file now enables the _secure_path_ option by default and preserves the `EDITOR`, `VISUAL`, and `SUDO_EDITOR` environment variables when running visudo. The new `--with-secure-path-value` configure option can be used to set the value of _secure_path_ in the default sudoers file. [GitHub issue #387](https://github.com/sudo-project/sudo/issues/387). * A sudoers schema for IBM Directory Server (aka IBM Tivoli Directory Server, IBM Security Directory Server, and IBM Security Verify Directory) is now included. * When cross-compiling sudo, the configure script now assumes that the snprintf() function is C99-compliant if the C compiler supports the C99 standard. Previously, configure would use sudo's own snprintf() when cross-compiling. [GitHub issue #386](https://github.com/sudo-project/sudo/issues/386).

* Fixed evaluation of the _lecture_, _listpw_, _verifypw_, and _fdexec_ sudoers Defaults settings when used without an explicit value. Previously, if specified without a value they were evaluated as boolean _false_, even when the negation operator ('!') was not present. * Fixed a bug introduced in sudo 1.9.14 that prevented LDAP netgroup queries using the `NETGROUP_BASE` setting from being performed. * Sudo will now transparently rename a user's lecture file from the older name-based path to the newer user-ID-based path. [GitHub issue #342](https://github.com/sudo-project/sudo/issues/342). * Fixed a bug introduced in sudo 1.9.15 that could cause a memory allocation failure if `sysconf(_SC_LOGIN_NAME_MAX)` fails. [Bug #1066](https://bugzilla.sudo.ws/show_bug.cgi?id=1066).

* Fixed a bug introduced in sudo 1.9.15 that could prevent a user's privileges from being listed by `sudo -l` if the sudoers entry in `/etc/nsswitch.conf` contains `[SUCCESS=return]`. This did not affect the ability to run commands via sudo. [Bug #1063](https://bugzilla.sudo.ws/show_bug.cgi?id=1063).

* Always disable core dumps when sudo sends itself a fatal signal. Fixes a problem where sudo could potentially dump core dump when it re-sends the fatal signal to itself. This is only an issue if the command received a signal that would normally result in a core dump but the command did not actually dump core. * Fixed a bug matching a command with a relative path name when the sudoers rule uses shell globbing rules for the path name. [Bug #1062](https://bugzilla.sudo.ws/show_bug.cgi?id=1062). * Permit visudo to be run even if the local host name is not set. [GitHub issue #332](https://github.com/sudo-project/sudo/issues/332). * Fixed an editing error introduced in sudo 1.9.15 that could prevent sudoreplay from replaying sessions correctly. [GitHub issue #334](https://github.com/sudo-project/sudo/issues/334). * Fixed a bug introduced in sudo 1.9.15 where "sudo -l > /dev/null" could hang on Linux systems. [GitHub issue #335](https://github.com/sudo-project/sudo/issues/335). * Fixed a bug introduced in sudo 1.9.15 where Solaris privileges specified in sudoers were not applied to the command being run.

* Fixed a bug on BSD systems where sudo would not restore the terminal settings on exit if the terminal had parity enabled. [GitHub issue #326](https://github.com/sudo-project/sudo/issues/326).