{"id":"BIT-python-2026-19445","summary":"Use-after-free of a server-side SSLContext when sni_callback switches contexts","details":"A remote, unauthenticated TLS client can make a server crash or call\nthrough a freed pointer if its sni_callback assigns a different context to\nSSLSocket.context (the documented way to select a certificate per server\nname) and nothing else keeps the original ssl.SSLContext alive. Typical\ncases are servers that create an SSLContext per connection or replace it\nwhile connections are open; servers that wrap their listening socket with\nit are not affected.\n\n\nMitigation: keep a reference to every SSLContext that sets sni_callback for\nthe lifetime of the server. TLS clients are not affected.","aliases":["BIT-libpython-2026-19445","BIT-python-min-2026-19445","CVE-2026-19445","PSF-2026-43"],"modified":"2026-10-09T12:10:32.528164652Z","published":"2026-10-09T10:52:46.026Z","database_specific":{"severity":"Critical","cpes":["cpe:2.3:a:python:python:*:*:*:*:*:*:*:*"]},"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2026/09/30/17"},{"type":"WEB","url":"https://github.com/python/cpython/commit/34a53dce8174da2fceb12fe084a4def02a10053d"},{"type":"WEB","url":"https://github.com/python/cpython/commit/46133cd57d309652139ada74014aca7665ac552b"},{"type":"WEB","url":"https://github.com/python/cpython/commit/63fab143d94cafae71850831acfb52041ba44af7"},{"type":"WEB","url":"https://github.com/python/cpython/commit/b12968cefe69ca1dcb8606c832ff73ee7dbf4ba8"},{"type":"WEB","url":"https://github.com/python/cpython/commit/cd7e51e7d4563866fbaa1e2521ae69b45daf3698"},{"type":"WEB","url":"https://github.com/python/cpython/commit/d8717ed01717a9641686e6e6f83f0ab8af235e2c"},{"type":"WEB","url":"https://github.com/python/cpython/commit/ec44b5a3258cbda947d5e07242ee562ed05ef24b"},{"type":"WEB","url":"https://github.com/python/cpython/issues/156293"},{"type":"WEB","url":"https://github.com/python/cpython/pull/158504"},{"type":"WEB","url":"https://mail.python.org/archives/list/security-announce@python.org/thread/QMQIUQB6WGGC3MI7I3WKQXOYOBDSPPS3/"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19445"}],"affected":[{"package":{"name":"python","ecosystem":"Bitnami","purl":"pkg:bitnami/python"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.10.22"},{"introduced":"3.11.0"},{"fixed":"3.11.17"},{"introduced":"3.12.0"},{"fixed":"3.12.15"},{"introduced":"3.13.0"},{"fixed":"3.13.16"},{"introduced":"3.14.0"},{"fixed":"3.14.8"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/python/BIT-python-2026-19445.json"},"severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}],"schema_version":"1.9.0"}