MEDIUM 5.3

PYSEC-2026-2268

Details

pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 0.14.0 and prior to version 26.0.0, 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. Starting in version 26.0.0, unhandled exceptions now result in rejecting the connection.

Are you affected?

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Affected packages

PyPI / pyopenssl

Introduced in: 0.14 Fixed in: 26.0.0

Fix pip install --upgrade 'pyopenssl>=26.0.0'

References

https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst#L27 [ADVISORY]
https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424 [ADVISORY]
https://github.com/pyca/pyopenssl/commit/d41a814759a9fb49584ca8ab3f7295de49a85aa0 [FIX]