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.
Published: 2026-09-18
Score: 7 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-3w57-8xmc-8v26 AnyIO run_process/open_process ignores extra_groups and can retain parent supplementary groups
History

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
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.
Title AnyIO run_process/open_process ignores extra_groups and can retain parent supplementary groups
Weaknesses CWE-266
CWE-269
References
Metrics cvssV4_0

{'score': 7, 'vector': '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'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-18T17:02:30.273Z

Reserved: 2026-07-16T14:14:24.386Z

Link: CVE-2026-63349

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-18T17:16:59.317

Modified: 2026-09-18T17:16:59.317

Link: CVE-2026-63349

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-19T12:30:17Z

Weaknesses
  • CWE-266

    Incorrect Privilege Assignment

  • CWE-269

    Improper Privilege Management