CVE-2026-86139 Integer overflow in libxml2
Medium 6.9
Published
Updated
Check this codebase for CVE-2026-86139 and fix it if it is affected.
What it is: CVE-2026-86139 is a medium-severity vulnerability in Xmlsoft Libxml2, published on 5 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-86139 in the wild and no public exploit code.
Affected product: Xmlsoft Libxml2. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-86139/ (Markdown: https://insights.sbomify.com/CVE-2026-86139/index.md)
An integer overflow in libxml2's URI escaping function can lead to denial of service, affecting applications using this library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-86139?
CVE-2026-86139 is a medium-severity vulnerability in Xmlsoft Libxml2, published on 5 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In libxml2 before 2.15.4, xmlURIEscapeStr in uri.c has an integer overflow.
Weakness: CWE-190
Which versions are affected by CVE-2026-86139?
It affects 1 product.
Products include Xmlsoft Libxml2.
How do I fix CVE-2026-86139?
Upgrade to a fixed version.
Is CVE-2026-86139 being exploited?
There is no known exploitation of CVE-2026-86139 in the wild and no public exploit code.
Other vulnerabilities in Xmlsoft Libxml2
Sources
Also known as AZL-99714, BELL-CVE-2026-86139, DEBIAN-CVE-2026-86139, ECHO-e3c1-3a3b-83ba, GHSA-xvw4-gjw8-rw38, UBUNTU-CVE-2026-86139.