Vulnerability · Published May 12, 2026 · Assigned by GitHub_M
CVE-2026-42300DevGuard: Unauthenticated identity assertion via `X-Admin-Token` header
Critical 9.3
In plain English
A critical-severity authentication bypass in devguard from l3montree-dev. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
DevGuard provides vulnerability management for the full software supply chain. Prior to 1.2.2, 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 over that organisation's DevGuard resources. This vulnerability is fixed in 1.2.2.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/l3montree-dev/devguard | 1.2.2 | GHSA-2g9v-7mr5-fgjg |
| Go | github.com/l3montree-dev/devguard | 1.2.2 | GO-2026-4988 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| l3montree-dev | devguard | < 1.2.2 |
Weakness: CWE-288 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N