GHSA-vp96-hxj8-p424
pyOpenSSL allows TLS connection bypass via unhandled callback exception in set_tlsext_servername_callback
Packages
Details
As written in the advisory (Markdown source, shown as plain text).
If a user provided callback to `set_tlsext_servername_callback` raised an unhandled exception, this would result in a connection being accepted. If a user was relying on this callback for any security-sensitive behavior, this could allow bypassing it.
Unhandled exceptions now result in rejecting the connection.
Credit to **Leury Castillo** for reporting this issue.
References
External links from the advisory. They lead to third-party sites.
- https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424
- https://nvd.nist.gov/vuln/detail/CVE-2026-27448
- https://github.com/pyca/pyopenssl/commit/d41a814759a9fb49584ca8ab3f7295de49a85aa0
- https://github.com/pyca/pyopenssl
- https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst#L27