# CVE-2026-55494: Tugtainer: Unauthenticated access to Tugtainer Agent Docker management APIs when AGENT_SECRET is unset

> Attackers can access Docker management APIs without authentication if the agent secret is unset, allowing unauthorized container control.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-wgw2-c96g-p7h7

## What is CVE-2026-55494?

CVE-2026-55494 is a critical authentication bypass vulnerability in Quenary tugtainer, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Tugtainer is a self-hosted app for automating updates of Docker containers. Prior to version 1.30.4, Tugtainer Agent allows unauthenticated access to Docker management APIs when AGENT_SECRET is not configured. The Agent uses request signatures to protect its API routes. However, in agent/auth.py, the signature verification function returns successfully if Config.AGENT_SECRET is empty. This causes protected Agent APIs to become accessible without authentication. This issue has been patched in version 1.30.4.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-55494?


## How do I fix CVE-2026-55494?

No fix has been published for CVE-2026-55494 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-55494 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55494 exists.

Public exploit code:

- A combination of CVE-2026-55494 and CVE-2026-62308 to get root privilege RCE in tugtainer (github_poc): https://github.com/4qu4r1um/tugtainer-1.30.2-CVE-2026-55494-and-CVE-2026-62308-to-RCE

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55494 and fix it if it is affected.

What it is: CVE-2026-55494 is a critical authentication bypass vulnerability in Quenary tugtainer, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55494 exists.

Affected product: Quenary tugtainer. 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-2026-55494/ (Markdown: https://insights.sbomify.com/CVE-2026-55494/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55494
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55494
- OSV: https://osv.dev/vulnerability/CVE-2026-55494

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55494/
Summaries are generated and may contain mistakes; the official description above is the record.