CVE-2026-27448

Publication date 18 March 2026

Last updated 5 June 2026

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

5.3 · Medium

Score breakdown

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.

Why is this CVE low priority?

This has been rated low severity by pyOpenSSL developers

Learn more about Ubuntu priority

Status

Package Ubuntu Release Status
pyopenssl 26.04 LTS resolute
Not affected
25.10 questing
Fixed 25.0.0-1ubuntu0.1
24.04 LTS noble
Fixed 23.2.0-1ubuntu0.1
22.04 LTS jammy
Fixed 21.0.0-1ubuntu0.1
20.04 LTS focal
Fixed 19.0.0-1ubuntu0.1~esm1
18.04 LTS bionic
Fixed 17.5.0-1ubuntu1+esm1
16.04 LTS xenial
Fixed 0.15.1-2ubuntu0.2+esm1
14.04 LTS trusty
Not affected

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
pyopenssl

Severity score breakdown

Parameter Value
Base score 5.3 · Medium
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact Low
Availability impact None
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References

Related Ubuntu Security Notices (USN)

Other references

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