# CVE-2026-113351: libexpat 2.7.2 through 2.9.0 Denial of Service via XML_ParserReset


- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 20 Oct 2026
- **Updated:** 20 Oct 2026
- **Also known as:** AZL-109989, BELL-CVE-2026-113351, DEBIAN-CVE-2026-113351, ECHO-8447-5ec2-6e1c, GHSA-6r6q-9jmv-gg3h, ROOT-OS-DEBIAN-13-CVE-2026-113351, UBUNTU-CVE-2026-113351

## What is CVE-2026-113351?

CVE-2026-113351 is a high-severity vulnerability in libexpat, published on 20 Oct 2026. 

### Official description

libexpat 2.7.2 through 2.9.0 contains a denial of service vulnerability because XML_ParserReset zeroes the direct byte count but never offsets tracked heap allocations. Attackers can submit a large XML document so later documents on the same reset parser fail with XML_ERROR_NO_MEMORY until it is recreated.

Weakness: CWE-909 (Missing Initialization of Resource)

## Which versions are affected by CVE-2026-113351?


## How do I fix CVE-2026-113351?

Upgrade to a fixed version.

## Is CVE-2026-113351 being exploited?

There is no known exploitation of CVE-2026-113351 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-113351 and fix it if it is affected.

What it is: CVE-2026-113351 is a high-severity vulnerability in libexpat, published on 20 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-113351 in the wild and no public exploit code.

Affected product: libexpat. 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-2026-113351/ (Markdown: https://insights.sbomify.com/CVE-2026-113351/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-113351
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-113351
- OSV: https://osv.dev/vulnerability/CVE-2026-113351

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-113351/
Summaries are generated and may contain mistakes; the official description above is the record.