# CVE-2026-78222: NGINX ngx_http_js_module vulnerability

> Remote attackers can crash NGINX workers by sending malformed HTTP responses to trusted JavaScript code using ngx.fetch().

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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-99300, DEBIAN-CVE-2026-78222, GHSA-27f9-cgjj-wvcv, UBUNTU-CVE-2026-78222

## What is CVE-2026-78222?

CVE-2026-78222 is a high-severity 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

A vulnerability exists in NGINX JavaScript where a malformed HTTP response received by ngx.fetch() can crash an NGINX worker when trusted JavaScript reads Response.statusText. Exploitation requires control or influence over the fetched HTTP response.

Impact:
This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system. 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-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-78222?


## How do I fix CVE-2026-78222?

Apply the vendor's patch.

## Is CVE-2026-78222 being exploited?

There is no known exploitation of CVE-2026-78222 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78222 and fix it if it is affected.

What it is: CVE-2026-78222 is a high-severity 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-2026-78222 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-2026-78222/ (Markdown: https://insights.sbomify.com/CVE-2026-78222/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78222
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78222
- OSV: https://osv.dev/vulnerability/CVE-2026-78222

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78222/
Summaries are generated and may contain mistakes; the official description above is the record.