# CVE-2026-82042: UTMStack < 11.2.16 Authentication Bypass via InternalApiKeyFilter

> Remote attackers can bypass authentication and gain full administrative API access by presenting a valid internal key header, allowing account creation and data exfiltration.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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:** No
- **Published:** 2 Oct 2026
- **Updated:** 5 Oct 2026
- **Also known as:** GHSA-phx4-fx7q-vfw9

## What is CVE-2026-82042?

CVE-2026-82042 is a critical authentication bypass vulnerability in UTMStack, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

UTMStack before 11.2.16 contains an authentication bypass vulnerability that allows remote attackers to gain full administrative API access by presenting a valid Utm-Internal-Key header matching the INTERNAL_KEY environment variable value, which the InternalApiKeyFilter accepts for any endpoint without path restriction, constant-time comparison, rate limiting, or audit logging. Attackers who obtain the key value can authenticate without a user account or JWT to create accounts, manage users, exfiltrate data, and modify security rules.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-82042?


## How do I fix CVE-2026-82042?

No fix has been published for CVE-2026-82042 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-82042 being exploited?

There is no known exploitation of CVE-2026-82042 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82042 and fix it if it is affected.

What it is: CVE-2026-82042 is a critical authentication bypass vulnerability in UTMStack, published on 2 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-2026-82042 in the wild and no public exploit code.

Affected product: UTMStack. 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-2026-82042/ (Markdown: https://insights.sbomify.com/CVE-2026-82042/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82042
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82042
- OSV: https://osv.dev/vulnerability/CVE-2026-82042

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82042/
Summaries are generated and may contain mistakes; the official description above is the record.