Go to homepageCyberStrike

Menu

Star on GitHub · 3.4k
Sign inDownload

CVE-2026-86143

6.9 · MEDIUM

In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calli…

Published Sep 5, 2026xmlsoftCWE-192EPSS 0.19%

Overview

CVE-2026-86143 is a medium-severity vulnerability affecting xmlsoft libxml2. It was published on September 5, 2026 and has a CVSS 3.1 base score of 6.9 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.9, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical description

In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback. This has security relevance for many types of uses of that length value within a callback.

Remediation

Check the references section for vendor advisories and patches from xmlsoft. Update libxml2 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected products

VendorProductVersionsStatus
xmlsoftlibxml2>= 0, < 2.15.4Affected

References

GitHubgithub.com/GNOME/libxml2/commit/90f293ba74d28b1d570920382e707586f68ebf35GitHubgithub.com/GNOME/libxml2/compare/v2.15.3...v2.15.4Refgitlab.gnome.org/GNOME/libxml2/-/work_items/1111

How CyberStrike helps

Frequently asked questions

What is CVE-2026-86143?

CVE-2026-86143 is a medium-severity vulnerability affecting xmlsoft libxml2. It was published on September 5, 2026 and has a CVSS 3.1 base score of 6.9 (MEDIUM).

How severe is CVE-2026-86143?

This vulnerability has a CVSS 3.1 base score of 6.9, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-86143?

Check the references section for vendor advisories and patches from xmlsoft. Update libxml2 to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-86143?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-86143 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

Related MEDIUM CVEs from 2026

View all
Browse by year2026202520242023202220212020201920182017201620152014201320122011201020092008200720062005200420032002200120001999
Watch the demo →