Detections
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pyOpenSSL 0.14.x < 26.0.0 Security Bypass

medium Nessus Plugin ID 318386

Synopsis

A Python library installed on the remote host is affected by a security bypass vulnerability.

Description

The version of pyOpenSSL installed on the remote host is prior to 26.0.0. It is, therefore, affected by a security bypass vulnerability:

 - 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-2026-27448)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to pyOpenSSL version 26.0.0 or later.

See Also

http://www.nessus.org/u?9be3fb16

http://www.nessus.org/u?f411998f

Plugin Details

Severity: Medium

ID: 318386

File Name: pyopenssl_CVE-2026-27448.nasl

Version: 1.1

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 6/3/2026

Updated: 6/3/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 1.4

CVSS v2

Risk Factor: Medium

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2026-27448

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v4

Risk Factor: Medium

Base Score: 6.3

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/a:pyopenssl:pyopenssl

Patch Publication Date: 3/18/2026

Vulnerability Publication Date: 3/18/2026

Reference Information

CVE: CVE-2026-27448

IAVA: 2026-A-0248