| Name | CVE-2026-19445 |
| Description | 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| pypy3 (PTS) | bookworm | 7.3.11+dfsg-2+deb12u3 | vulnerable |
| trixie | 7.3.19+dfsg-2 | vulnerable | |
| forky, sid | 8.0.0+dfsg-1 | vulnerable | |
| python3.11 (PTS) | bookworm | 3.11.2-6+deb12u8 | vulnerable |
| bookworm (security) | 3.11.2-6+deb12u3 | vulnerable | |
| python3.13 (PTS) | trixie | 3.13.5-2+deb13u5 | vulnerable |
| forky, sid | 3.13.15-1 | vulnerable | |
| python3.14 (PTS) | forky | 3.14.7-4 | vulnerable |
| sid | 3.14.7-5 | vulnerable | |
| python3.15 (PTS) | forky, sid | 3.15.0~rc2-3 | vulnerable |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| pypy3 | source | (unstable) | (unfixed) | |||
| python3.11 | source | (unstable) | (unfixed) | |||
| python3.13 | source | (unstable) | (unfixed) | |||
| python3.14 | source | (unstable) | (unfixed) | |||
| python3.15 | source | (unstable) | (unfixed) |
https://github.com/python/cpython/issues/156293
https://github.com/python/cpython/pull/158504
https://github.com/python/cpython/commit/63fab143d94cafae71850831acfb52041ba44af7 (3.15 branch)
https://github.com/python/cpython/commit/cd7e51e7d4563866fbaa1e2521ae69b45daf3698 (3.14 branch)
https://github.com/python/cpython/commit/d8717ed01717a9641686e6e6f83f0ab8af235e2c (3.13 branch)
https://github.com/python/cpython/pull/158523 (3.11)