CVE-2021-23240

Name	CVE-2021-23240
Description	selinux_edit_copy_tfiles in sudoedit in Sudo before 1.9.5 allows a local unprivileged user to gain file ownership and escalate privileges by replacing a temporary file with a symlink to an arbitrary file target. This affects SELinux RBAC support in permissive mode. Machines without SELinux are not vulnerable.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severity	medium

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
sudo (PTS)	stretch	1.8.19p1-2.1+deb9u2	vulnerable
	stretch (security)	1.8.19p1-2.1+deb9u3	vulnerable
	buster, buster (security)	1.8.27-1+deb10u3	vulnerable
	bullseye, sid	1.9.5p2-3	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
sudo	source	(unstable)	1.9.5-1	unimportant

Notes

https://www.openwall.com/lists/oss-security/2021/01/11/2
https://www.sudo.ws/repos/sudo/rev/8fcb36ef422a
https://www.sudo.ws/alerts/sudoedit_selinux.html
Neutralised by kernel hardening (fs.protected_symlinks = 1)