# CVE-2026-18329: NGINX ngx_http_js_module vulnerability

> An unauthenticated attacker can bypass js_access controls by triggering an exception during asynchronous body processing, gaining unauthorized access to protected resources.

- **Severity:** High 8.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/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:** 2 Sep 2026
- **Updated:** 2 Sep 2026
- **Also known as:** AZL-99303, DEBIAN-CVE-2026-18329, GHSA-jm9r-m8jm-j2hr, UBUNTU-CVE-2026-18329

## What is CVE-2026-18329?

CVE-2026-18329 is a high-severity authentication bypass vulnerability in F5 NGINX JavaScript, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Description

NGINX JavaScript (njs) and QuickJS (qjs) engines have a vulnerability when a js_access handler performs asynchronous request body processing and an exception is thrown during asynchronous access-control evaluation before an explicit access denial is returned. An unauthenticated attacker can exploit this vulnerability by sending a crafted HTTP request that triggers an error condition in the access validation logic. This may cause the js_access phase to fail open, allowing the request to proceed instead of being denied, resulting in an authentication or authorization bypass and unauthorized access to protected resources.

Impact

This vulnerability may allow remote attackers to bypass js_access controls. 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-636 (Not Failing Securely)

## Which versions are affected by CVE-2026-18329?


## How do I fix CVE-2026-18329?

Apply the vendor's patch.

## Is CVE-2026-18329 being exploited?

There is no known exploitation of CVE-2026-18329 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18329 and fix it if it is affected.

What it is: CVE-2026-18329 is a high-severity authentication bypass vulnerability in F5 NGINX JavaScript, published on 2 Sep 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-2026-18329 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-2026-18329/ (Markdown: https://insights.sbomify.com/CVE-2026-18329/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18329
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18329
- OSV: https://osv.dev/vulnerability/CVE-2026-18329

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18329/
Summaries are generated and may contain mistakes; the official description above is the record.