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.
Metrics
Affected Vendors & Products
References
History
Wed, 23 Sep 2026 00:15:00 +0000
| Type | Values Removed | Values Added |
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| Weaknesses | CWE-1322 | |
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threat_severity
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cvssV3_1
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Mon, 21 Sep 2026 10:45:00 +0000
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Agronholm
Agronholm anyio |
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| Vendors & Products |
Agronholm
Agronholm anyio |
Fri, 18 Sep 2026 21:30:00 +0000
| Type | Values Removed | Values Added |
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| 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. | |
| Title | AnyIO process-pool workers can block indefinitely on undrained stderr | |
| Weaknesses | CWE-770 | |
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-09-18T17:04:32.038Z
Updated: 2026-09-18T18:07:27.772Z
Reserved: 2026-07-20T18:31:39.290Z
Link: CVE-2026-64847
Updated: 2026-09-18T18:07:23.520Z
Status : Deferred
Published: 2026-09-18T18:17:10.930
Modified: 2026-09-24T21:25:27.050
Link: CVE-2026-64847