CVE-2026-64847
AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio.
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | anyio | < 4.14.2 | 4.14.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-5p39-cfhj-2xmp
- https://github.com/agronholm/anyio/security/advisories/GHSA-5p39-cfhj-2xmp
- https://github.com/agronholm/anyio/pull/1207
- https://github.com/agronholm/anyio/commit/f1b7301c8264b0d2e8d24a5788fd29e93dea4040
- https://github.com/agronholm/anyio/releases/tag/4.14.2