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.
History

Sat, 26 Sep 2026 07:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 23 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-648
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'}

threat_severity

Moderate


Mon, 21 Sep 2026 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Agronholm
Agronholm anyio
Vendors & Products Agronholm
Agronholm anyio

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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

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

Updated: 2026-09-24T21:05:25.977Z

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

Link: CVE-2026-63349

cve-icon Vulnrichment

Updated: 2026-09-24T21:03:48.920Z

cve-icon NVD

Status : Awaiting Analysis

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

Modified: 2026-09-25T14:10:13.927

Link: CVE-2026-63349

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-18T17:02:30Z

Links: CVE-2026-63349 - Bugzilla