CVE-2026-64847
Publication date 21 September 2026
Last updated 21 September 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| python-anyio | 26.04 LTS resolute |
Needs evaluation
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
Severity score breakdown
CVSS version: CVSS v4.0
Base score
6.8 · Medium
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
References
Other references
- https://www.cve.org/CVERecord?id=CVE-2026-64847
- 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 (4.14.2)
- https://github.com/agronholm/anyio/commit/f1b7301c8264b0d2e8d24a5788fd29e93dea4040
- https://github.com/agronholm/anyio/releases/tag/4.14.2