Hi,

The following vulnerability was published for pypy3.

CVE-2026-19445[0]:
| 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.

Fix in cpython:
https://github.com/python/cpython/issues/156293
https://github.com/python/cpython/pull/158504
https://github.com/python/cpython/pull/158523 (3.11)


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-19445
https://www.cve.org/CVERecord?id=CVE-2026-19445

Please adjust the affected versions in the BTS as needed.