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DevGuard has an unauthenticated identity assertion via `X-Admin-Token` header — CVE-2026-42300

GitHub · GitHub · CVE-2026-42300

ID
CVE-2026-42300
Date
Updated
Activity
Source
GitHub
Vendor
GitHub
Threat
critical
CVSS
9.3
EPSS
0.0005

Summary

### Impact The `SessionMiddleware` accepts a client-supplied `X-Admin-Token` HTTP request header and uses its raw string value as the authenticated `userID` when no Kratos session cookie is present. An unauthenticated attacker who knows or can guess a target user's Kratos identity UUID can issue requests as that user. Where the target user is an organisation `admin` or `owner`, this gives the attacker full control…

Product

go: github.com/l3montree-dev/devguard

What to do

General, cautious steps (verify details in the official source):

  • Prioritize patching or mitigation immediately (treat as actively risky).
  • Identify affected product versions in your inventory and verify whether you are impacted.
  • Apply vendor patches/updates or recommended mitigations as soon as available.
  • Read the official advisory for exact affected versions and remediation steps.

Official advisory

Related advisories