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Advisory record · GHSA-3w57-8xmc-8v26

AnyIO run_process/open_process ignores extra_groups and can retain parent supplementary groups

CVSS 7.0 HighEPSS 0.0011 · 1st percentile

Published by the GitHub Advisory Database at 18 Sept 2026, 17:17 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
anyioPyPI>=4.14.0, <4.14.24.14.2
Identifiers
GHSA-3w57-8xmc-8v26 · CVE-2026-63349 · PYSEC-2026-4023
Weakness (CWE)
CWE-266 · CWE-269
Tags
Published
18 Sept 2026
Updated
1 Oct 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

AnyIO versions 4.14.0 up to but not including 4.14.2 mishandle the extra_groups argument to anyio.run_process() and anyio.open_process() on POSIX systems. Because open_process() forwards the wrong variable, child processes can keep the parent's supplementary groups, and supplying group as well causes a TypeError. The source does not describe a remote attack; the risk is to applications that rely on these calls to drop privileges. Upgrade to AnyIO 4.14.2. No workaround is listed.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
7.0 High 4.0 CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0011, the 1st percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:09 UTC First seen by agentprime
  2. 31 Oct 2026, 14:09 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.