{"id":"UBUNTU-CVE-2025-43859","details":"h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, a leniency in h11's parsing of line terminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions. This issue has been patched in version 0.16.0. Since exploitation requires the combination of buggy h11 with a buggy (reverse) proxy, fixing either component is sufficient to mitigate this issue.","modified":"2026-01-30T02:13:21.381928Z","published":"2025-04-24T19:15:00Z","related":["USN-7503-1"],"upstream":["CVE-2025-43859"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2025-43859"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2025-43859"},{"type":"REPORT","url":"https://github.com/python-hyper/h11/security/advisories/GHSA-vqfr-h8mv-ghfj"},{"type":"REPORT","url":"https://github.com/python-hyper/h11/commit/114803a29ce50116dc47951c690ad4892b1a36ed"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-7503-1"}],"affected":[{"package":{"name":"python-h11","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-h11@0.14.0-1ubuntu0.24.04.1?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.14.0-1ubuntu0.24.04.1"}]}],"versions":["0.14.0-1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"python3-h11","binary_version":"0.14.0-1ubuntu0.24.04.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-43859.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}