# CVE-2026-101025: NGINX ngx_http_js_module vulnerability

> An unauthenticated attacker can cause denial of service in NGINX by sending malformed XML requests that trigger memory leaks in the njs engine.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Oct 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-108455, BELL-CVE-2026-101025, DEBIAN-CVE-2026-101025, GHSA-4jj4-r79f-9v3x, UBUNTU-CVE-2026-101025

## What is CVE-2026-101025?

CVE-2026-101025 is a medium-severity denial of service vulnerability in F5 NGINX JavaScript, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Description

NGINX JavaScript (njs) has a vulnerability where the built-in njs engine leaks a libxml2 parser context when xml.parse() fails. The failure path did not register cleanup and the context was not released for the lifetime of the process. An unauthenticated attacker may send requests with malformed XML and can cause unbounded memory growth in long-lived NGINX worker processes.

Impact

This vulnerability may allow remote attackers to send requests that trigger repeated parsing of malformed XML and may lead to NGINX worker termination or denial of service. There is no control plane exposure; this is a data plane issue only.

 Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-101025?


## How do I fix CVE-2026-101025?

Upgrade to a fixed version.

## Is CVE-2026-101025 being exploited?

There is no known exploitation of CVE-2026-101025 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101025 and fix it if it is affected.

What it is: CVE-2026-101025 is a medium-severity denial of service vulnerability in F5 NGINX JavaScript, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-101025 in the wild and no public exploit code.

Affected product: F5 NGINX JavaScript. 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-2026-101025/ (Markdown: https://insights.sbomify.com/CVE-2026-101025/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101025
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101025
- OSV: https://osv.dev/vulnerability/CVE-2026-101025

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101025/
Summaries are generated and may contain mistakes; the official description above is the record.