Vulnerability · Published Sep 30, 2026 · Assigned by GitHub_M

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

Critical 9.8

In plain English

A critical-severity improper access control in tugtainer from Quenary. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 51% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)0.6%top 49.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack tooling1Public PoC

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.

Affected products (as reported)

Vendor	Product	Versions
Quenary	tugtainer	< 1.30.4

Weakness: CWE-284 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

https://github.com/Quenary/tugtainer/security/advisories/GHSA-wgw2-c96g-p7h7 x_refsource_CONFIRM
https://github.com/Quenary/tugtainer/commit/0052a5544e187a4d12f771838a8a23ca4afb61cd x_refsource_MISC
https://github.com/Quenary/tugtainer/releases/tag/v1.30.4 x_refsource_MISC