AnyIO run_process/open_process ignores extra_groups and can retain parent supplementary groups
Key facts
- Attack vector
- Local
- Privileges required
- High
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- Present
- Impact type
- Privilege escalation
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Partial Red Hat: 15 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-266.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| agronholm | anyio | 4.14.0 to before 4.14.2 | 4.14.2 | Patch available | CNA |
| — | anyio (PyPI) | 4.14.0 to before 4.14.2 | 4.14.2 | Patch available | GHSA-3w57-8xmc-8v26 |
- anyio Vendoragronholm Affected 4.14.0 to before 4.14.2 Fixed in 4.14.2 Patch available CNA
- anyio (PyPI) Vendor— Affected 4.14.0 to before 4.14.2 Fixed in 4.14.2 Patch available GHSA-3w57-8xmc-8v26
Remediation
- Fix · CNA anyio (agronholm) Fixed in 4.14.2
- Fix · GHSA-3w57-8xmc-8v26 anyio (PyPI) Fixed in 4.14.2 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Ansible Automation Orchestrator 2026 | Affected | No fix yet: Fix deferred |
| Confidential Compute Attestation | Affected | No fix yet: Fix deferred |
| Exploit Intelligence | Affected | No fix planned: Out of support scope |
| Lightspeed Core | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Applications 8 | Affected | No fix yet: Fix deferred |
| Migration Toolkit for Containers | Affected | No fix yet: Fix deferred |
| OpenShift Lightspeed | Affected | No fix yet: Fix deferred |
| Red Hat AI Inference Server | Affected | No fix yet: Fix deferred |
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux command line assistant | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Virtualization 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenStack Platform 18.0 | Affected | No fix yet: Fix deferred |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Hardened Images
Timeline
- 2026-10-02 Threatist record created from CVE-2026-63349
- 2026-10-03 Alias added: GHSA-3w57-8xmc-8v26
References
More agronholm vulnerabilities
- TI-2026-21200 cbor2 has a Denial of Service via Uncontrolled Recursion in cbor2.loads CVSS 3.0HIGH 7.5
- TI-2024-17225 CBOR2 decoder has potential buffer overflow CVSS 3.1HIGH 7.5
- TI-2025-39535 Multiple vulnerabilities exist in cbor2 through version 5.7.0 in the… CVSS 3.1HIGH 7.5
- TI-2025-41712 CBORDecoder reuse can leak shareable values across decode calls CVSS 4.0MEDIUM 5.5
- TI-2026-45177 AnyIO: TLSStream IDNA 2003 host name encoding enables potential TLS certificate spoofing CVSS 4.0CRITICAL 9.3
- TI-2026-46365 AnyIO process-pool workers can block indefinitely on undrained stderr CVSS 4.0MEDIUM 6.8
Sources
- CVE-2026-63349 · CVE Program
- CVE-2026-63349 · NVD
- FIRST EPSS
- GHSA-3w57-8xmc-8v26 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-63349 · Red Hat security data · CC BY 4.0
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