# CVE-2026-55494: Tugtainer Agent authentication bypass when AGENT_SECRET not configured

Source: https://junglewise.ai/threats/cve-2026-55494-tugtainer-is-a-self-hosted-app-for-automating-updates-of-docker  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-30. Updated: 2026-09-30  
License: CC BY 4.0 with a link back

CVE-2026-55494 · Severity: critical · CVSS 9.8 · Published 2026-09-30

Tugtainer is a self-hosted application that automates Docker container updates. Prior to version 1.30.4, the Tugtainer Agent component fails to enforce authentication when the AGENT_SECRET configuration variable is not set, allowing unauthenticated attackers to access Docker management APIs. This could enable complete control over containerized workloads and data exfiltration from a compromised system.

Technologies: [Quenary Tugtainer](https://junglewise.ai/threats/technologies/tugtainer). Vendors: [Quenary](https://junglewise.ai/threats/vendors/quenary).

## Quick answers

**Is CVE-2026-55494 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55494 being exploited in the wild.

**How severe is CVE-2026-55494?** Critical severity, with a CVSS score of 9.8, published 30 September 2026.

**Which products and versions are affected?** Quenary Tugtainer before 1.30.4.

**Is there a fix for CVE-2026-55494?** A patch was published on 2026-06-13. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-55494 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-55494?** Check whether you run Quenary Tugtainer at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in agent/auth.py where the signature verification function returns success when Config.AGENT_SECRET is empty, bypassing the request signature checks that protect Agent API routes. An unauthenticated network attacker can call protected APIs without valid credentials, gaining full access to Docker management functions. The issue was patched in version 1.30.4 by making AGENT_SECRET mandatory.

## Affected products

- Quenary Tugtainer before 1.30.4

## Timeline

- 2026-09-30: disclosed
- 2026-06-13: patched

## References

- [https://github.com/Quenary/tugtainer/commit/0052a5544e187a4d12f771838a8a23ca4afb61cd](https://github.com/Quenary/tugtainer/commit/0052a5544e187a4d12f771838a8a23ca4afb61cd)
- [https://github.com/Quenary/tugtainer/releases/tag/v1.30.4](https://github.com/Quenary/tugtainer/releases/tag/v1.30.4)

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