{"id":"CVE-2026-19445","published":"2026-09-30T17:16:45.720","lastModified":"2026-10-03T01:17:24.930","description":"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.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":["CWE-416"],"vendors":[],"products":[],"references":[{"url":"https://github.com/python/cpython/commit/34a53dce8174da2fceb12fe084a4def02a10053d","tags":[]},{"url":"https://github.com/python/cpython/commit/46133cd57d309652139ada74014aca7665ac552b","tags":[]},{"url":"https://github.com/python/cpython/commit/63fab143d94cafae71850831acfb52041ba44af7","tags":[]},{"url":"https://github.com/python/cpython/commit/b12968cefe69ca1dcb8606c832ff73ee7dbf4ba8","tags":[]},{"url":"https://github.com/python/cpython/commit/cd7e51e7d4563866fbaa1e2521ae69b45daf3698","tags":[]},{"url":"https://github.com/python/cpython/commit/d8717ed01717a9641686e6e6f83f0ab8af235e2c","tags":[]},{"url":"https://github.com/python/cpython/commit/ec44b5a3258cbda947d5e07242ee562ed05ef24b","tags":[]},{"url":"https://github.com/python/cpython/issues/156293","tags":[]},{"url":"https://github.com/python/cpython/pull/158504","tags":[]},{"url":"https://mail.python.org/archives/list/security-announce@python.org/thread/QMQIUQB6WGGC3MI7I3WKQXOYOBDSPPS3/","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/09/30/17","tags":[]}],"exploitRefs":[{"url":"https://github.com/python/cpython/commit/34a53dce8174da2fceb12fe084a4def02a10053d","tags":[]},{"url":"https://github.com/python/cpython/commit/46133cd57d309652139ada74014aca7665ac552b","tags":[]},{"url":"https://github.com/python/cpython/commit/63fab143d94cafae71850831acfb52041ba44af7","tags":[]},{"url":"https://github.com/python/cpython/commit/b12968cefe69ca1dcb8606c832ff73ee7dbf4ba8","tags":[]},{"url":"https://github.com/python/cpython/commit/cd7e51e7d4563866fbaa1e2521ae69b45daf3698","tags":[]},{"url":"https://github.com/python/cpython/commit/d8717ed01717a9641686e6e6f83f0ab8af235e2c","tags":[]},{"url":"https://github.com/python/cpython/commit/ec44b5a3258cbda947d5e07242ee562ed05ef24b","tags":[]},{"url":"https://github.com/python/cpython/issues/156293","tags":[]},{"url":"https://github.com/python/cpython/pull/158504","tags":[]}],"hasPoc":true,"ai":null}