CVE-2026-19445 Affecting python3 package, versions <3.12.15-r0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-ALPINE323-PYTHON3-20364516
- published1 Oct 2026
- disclosed30 Sept 2026
Introduced: 30 Sep 2026
NewCVE-2026-19445 (opens in a new tab)How to fix?
Upgrade Alpine:3.23 python3 to version 3.12.15-r0 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream python3 package and not the python3 package as distributed by Alpine.
See How to fix? for Alpine:3.23 relevant fixed versions and status.
A remote, unauthenticated TLS client can make a server crash or call through a freed pointer if its sni_callback assigns a different context to SSLSocket.context (the documented way to select a certificate per server name) and nothing else keeps the original ssl.SSLContext alive. Typical cases are servers that create an SSLContext per connection or replace it while connections are open; servers that wrap their listening socket with it are not affected.
Mitigation: keep a reference to every SSLContext that sets sni_callback for the lifetime of the server. TLS clients are not affected.
References
- https://github.com/python/cpython/issues/156293
- https://github.com/python/cpython/pull/158504
- https://mail.python.org/archives/list/security-announce@python.org/thread/QMQIUQB6WGGC3MI7I3WKQXOYOBDSPPS3/
- http://www.openwall.com/lists/oss-security/2026/09/30/17
- https://github.com/python/cpython/commit/34a53dce8174da2fceb12fe084a4def02a10053d
- https://github.com/python/cpython/commit/46133cd57d309652139ada74014aca7665ac552b
- https://github.com/python/cpython/commit/63fab143d94cafae71850831acfb52041ba44af7
- https://github.com/python/cpython/commit/cd7e51e7d4563866fbaa1e2521ae69b45daf3698
- https://github.com/python/cpython/commit/d8717ed01717a9641686e6e6f83f0ab8af235e2c
- https://github.com/python/cpython/commit/b12968cefe69ca1dcb8606c832ff73ee7dbf4ba8
- https://github.com/python/cpython/commit/ec44b5a3258cbda947d5e07242ee562ed05ef24b