{"id":"UBUNTU-CVE-2026-64847","details":"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.","modified":"2026-09-23T23:32:57Z","published":"2026-09-18T18:17:00Z","upstream":["CVE-2026-64847"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-64847"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-64847"},{"type":"REPORT","url":"https://github.com/agronholm/anyio/security/advisories/GHSA-5p39-cfhj-2xmp"},{"type":"REPORT","url":"https://github.com/agronholm/anyio/pull/1207"},{"type":"REPORT","url":"https://github.com/agronholm/anyio/commit/f1b7301c8264b0d2e8d24a5788fd29e93dea4040"},{"type":"REPORT","url":"https://github.com/agronholm/anyio/commit/f1b7301c8264b0d2e8d24a5788fd29e93dea4040"},{"type":"REPORT","url":"https://github.com/agronholm/anyio/releases/tag/4.14.2"}],"affected":[{"package":{"name":"python-anyio","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/python-anyio?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.2-2","3.5.0-2ubuntu1","3.5.0-3ubuntu2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-anyio","binary_version":"3.5.0-3ubuntu2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64847.json"}},{"package":{"name":"python-anyio","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-anyio?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.7.0-1","4.2.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-anyio","binary_version":"4.2.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64847.json"}},{"package":{"name":"python-anyio","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/python-anyio?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.8.0-3","4.11.0-2","4.11.0-3"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-anyio","binary_version":"4.11.0-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-64847.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"},{"type":"Ubuntu","score":"medium"}]}