CVE-2021-4034

Name	CVE-2021-4034
Description	A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is a setuid tool designed to allow unprivileged users to run commands as privileged users according predefined policies. The current version of pkexec doesn't handle the calling parameters count correctly and ends trying to execute environment variables as commands. An attacker can leverage this by crafting environment variables in such a way it'll induce pkexec to execute arbitrary code. When successfully executed the attack can cause a local privilege escalation given unprivileged users administrative rights on the target machine.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-2899-1, DSA-5059-1, ELA-551-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
policykit-1 (PTS)	jessie, jessie (lts)	0.105-15~deb8u5	fixed
	stretch (security), stretch (lts), stretch	0.105-18+deb9u2	fixed
	buster (security), buster, buster (lts)	0.105-25+deb10u1	fixed
	bullseye (security), bullseye	0.105-31+deb11u1	fixed
	bookworm	122-3	fixed
	sid, trixie	125-2	fixed

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

Package	Type	Release	Fixed Version	Origin
policykit-1	source	jessie	0.105-15~deb8u5	ELA-551-1
policykit-1	source	stretch	0.105-18+deb9u2	DLA-2899-1
policykit-1	source	buster	0.105-25+deb10u1	DSA-5059-1
policykit-1	source	bullseye	0.105-31+deb11u1	DSA-5059-1
policykit-1	source	(unstable)	0.105-31.1

Notes

https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt
https://gitlab.freedesktop.org/polkit/polkit/-/commit/a2bf5c9c83b6ae46cbd5c779d3055bff81ded683
https://www.openwall.com/lists/oss-security/2022/01/25/11