CVE-2026-19445 (GCVE-0-2026-19445)

Vulnerability from cvelistv5 – Published: 2026-09-30 16:16 – Updated: 2026-10-03 00:36
VLAI
Title
Use-after-free of a server-side SSLContext when sni_callback switches contexts
Summary
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.
Severity
9.2 (Critical)
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
Assigner
PSF CNA under the mitre root
CNA scorecard B 80/100 over 27 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Python Software Foundation CPython Affected: 0 , < 3.10.22 (python)
Affected: 3.11.0 , < 3.11.17 (python)
Affected: 3.12.0 , < 3.12.15 (python)
Affected: 3.13.0 , < 3.13.16 (python)
Affected: 3.14.0 , < 3.14.8 (python)
Affected: 3.15.0a1 , < 3.15.0rc3 (python)
guessed Create a notification for this product.
Credits
Gregory P. Smith (https://github.com/gpshead) Seth Larson (https://github.com/sethmlarson) Bénédikt Tran (https://github.com/picnixz)
Show details on NVD website
To clipboard 

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}



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