CVE-2026-64847
Severity CVSS v4.0:
MEDIUM
Type:
Unavailable / Other
Publication date:
18/09/2026
Last modified:
24/09/2026
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.
Impact
Base Score 4.0
6.80
Severity 4.0
MEDIUM