Summary
DevGuard has an unauthenticated identity assertion via X-Admin-Token header
Workarounds
Configure a reverse proxy to strip the X-Admin-Token header before sending requests to the DevGuard API.
Resources
Fixed commit: https://github.com/l3montree-dev/devguard/commit/6f38310bf93b2a63df3055038f4da82b1f4e6d9a
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 over that organisation's DevGuard resources.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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The release v1.2.2 patches this issue. Update your DevGuard API Instances to this version.
Frequently Asked Questions
- What is CVE-2026-42300? CVE-2026-42300 is a critical-severity security vulnerability in github.com/l3montree-dev/devguard (go), affecting versions < 1.2.2. It is fixed in 1.2.2.
- Which versions of github.com/l3montree-dev/devguard are affected by CVE-2026-42300? github.com/l3montree-dev/devguard (go) versions < 1.2.2 is affected.
- Is there a fix for CVE-2026-42300? Yes. CVE-2026-42300 is fixed in 1.2.2. Upgrade to this version or later.
- Is CVE-2026-42300 exploitable, and should I be worried? Whether CVE-2026-42300 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-42300 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-42300? Upgrade
github.com/l3montree-dev/devguardto 1.2.2 or later.