CVE-2026-87004 json
Tugtainer: OIDC id_token claims accepted without signature/audience/expiry verification
published 2026-09-30 39 d ago modified 2026-09-30 39 d ago also EUVD-2026-90195
- cvss
- 8.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 27%
- public exploits
- 0
- none known
Summary
Tugtainer is a self-hosted app for automating updates of Docker containers. Prior to version 1.31.3, when the OIDC login flow completes, backend/modules/auth/providers/auth_oidc_provider.py decodes the id_token returned by the identity provider's token endpoint using jose.jwt.get_unverified_claims() instead of jwt.decode(). This skips signature verification, audience (aud) validation, issuer (iss) validation, and expiry (exp) checking entirely. The extracted claims (email/sub/preferred_username) are then used directly as the user_id for the resulting Tugtainer session. This issue has been patched in version 1.31.3.
Patch / fix
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 39 d ago
Exploit prediction
0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/Quenary/tugtainer/security/advisories/GHSA-crjc-6vc7-xrfh referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
- Quenary tugtainer
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
Sources
- CVE List CVE-2026-87004
- NVD CVE-2026-87004
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