Vulnerability · Published Jun 2, 2026 · Assigned by GitHub_M
CVE-2026-42073OpenClaude's MCP OAuth Callback: State Check Bypass via error Param Leads to DoS
Medium 6.5
In plain English
A medium-severity cross-site request forgery in openclaude from Gitlawb. Proof-of-concept exploit code is public. 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
OpenClaude is an open-source coding-agent command line interface for cloud and local model providers. Prior to version 0.5.1, the OpenClaude MCP authentication flow starts a temporary local HTTP server to handle OAuth callbacks. To prevent CSRF attacks, the server validates a state parameter against an internally stored value. However, due to a logic flaw in the order of conditionals, an attacker can completely bypass this check and force the server to shut down — without knowing the state value at all. This issue has been patched in version 0.5.1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @gitlawb/openclaude | 0.5.1 | GHSA-c73c-x77g-854r |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Gitlawb | openclaude | < 0.5.1 |
Weakness: CWE-352, CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H