{"id":"CVE-2026-19445","title":"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 el…","summary":"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 el…","severity":"critical","cvss":9.2,"cvssVector":"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","cwe":["CWE-416"],"vendor":"Python Software Foundation","product":"CPython","affected":["CPython < 3.15.0"],"published":"2026-09-30","updated":"2026-09-30","sourceUpdated":"2026-09-30T21:17:10.140","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-19445","references":[{"url":"https://github.com/python/cpython/commit/34a53dce8174da2fceb12fe084a4def02a10053d","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/46133cd57d309652139ada74014aca7665ac552b","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/63fab143d94cafae71850831acfb52041ba44af7","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/cd7e51e7d4563866fbaa1e2521ae69b45daf3698","label":"cna@python.org"},{"url":"https://github.com/python/cpython/commit/d8717ed01717a9641686e6e6f83f0ab8af235e2c","label":"cna@python.org"},{"url":"https://github.com/python/cpython/issues/156293","label":"cna@python.org"},{"url":"https://github.com/python/cpython/pull/158504","label":"cna@python.org"},{"url":"https://mail.python.org/archives/list/security-announce@python.org/thread/QMQIUQB6WGGC3MI7I3WKQXOYOBDSPPS3/","label":"cna@python.org"},{"url":"http://www.openwall.com/lists/oss-security/2026/09/30/17","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd","cve.org"],"cvssSource":"cna","ingestedAt":"2026-09-30T17:13:20.841Z","slug":"CVE-2026-19445","body":"## Overview\n\nA 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":51,"depthScoreParts":{"impact":50.6,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}