CVE-2026-63349

Name	CVE-2026-63349
Description	AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. In 4.14.0, AnyIO accepts the POSIX extra_groups argument in anyio.run_process() and anyio.open_process(), but open_process() forwards the group argument to the backend instead of extra_groups. A caller that supplies extra_groups=[] to clear inherited supplementary groups can therefore launch a child that retains the parent process groups, undermining a privilege-dropping boundary. If group is also supplied, the integer group value is passed where an iterable of supplementary groups is expected and the launch can fail with TypeError. This issue affects POSIX applications that rely on AnyIO subprocess helpers to launch less-privileged child processes. This issue is fixed in version 4.14.2.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1148561

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
python-anyio (PTS)	bookworm	3.6.2-1	vulnerable
	trixie	4.8.0-3	vulnerable
	forky, sid	4.12.1-3	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
python-anyio	source	(unstable)	(unfixed)			1148561

Notes

https://github.com/agronholm/anyio/security/advisories/GHSA-3w57-8xmc-8v26
https://github.com/agronholm/anyio/pull/1209
https://github.com/agronholm/anyio/commit/eb562e6462ee46b1904e50b02ce00a858cdeb200 (4.14.2)