Vulnerability Description
AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. Prior to 4.14.2, AnyIO starts process-pool workers with standard error connected to a pipe that the parent never drains, even though the documented behavior redirects all three standard streams. Worker code that writes enough attacker-influenced data to sys.stderr can fill the pipe and block before returning the standard-output protocol response, causing the awaiting process-pool call to remain blocked indefinitely. Applications that run untrusted or faulty worker code capable of producing substantial standard-error output are affected. This issue is fixed in version 4.14.2.
Related Weaknesses (CWE)
References
- https://github.com/agronholm/anyio/commit/f1b7301c8264b0d2e8d24a5788fd29e93dea40
- https://github.com/agronholm/anyio/pull/1207
- https://github.com/agronholm/anyio/releases/tag/4.14.2
- https://github.com/agronholm/anyio/security/advisories/GHSA-5p39-cfhj-2xmp
FAQ
What is CVE-2026-64847?
CVE-2026-64847 is a documented vulnerability. AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. Prior to 4.14.2, AnyIO starts process-pool workers with standard error connected to...
How severe is CVE-2026-64847?
CVSS scoring is not yet available for CVE-2026-64847. Check NVD for updates.
Is there a patch for CVE-2026-64847?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.