CVE-2026-27448

MEDIUM

5.3

Description

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.

CVE Details

CVSS v3.1 Score5.3

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published3/18/2026

Last Modified3/23/2026

Sourcenvd

Honeypot Sightings0

Affected Products

pyopenssl:pyopenssl

Weaknesses (CWE)

CWE-636

References

https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst#L27(security-advisories@github.com)

https://github.com/pyca/pyopenssl/commit/d41a814759a9fb49584ca8ab3f7295de49a85aa0(security-advisories@github.com)

https://github.com/pyca/pyopenssl/security/advisories/GHSA-vp96-hxj8-p424(security-advisories@github.com)

IOC Correlations

No correlations recorded

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