What’s Vulnerable › Vulnerabilities

CVE-2026-42073: OpenClaude's MCP OAuth Callback: State Check Bypass via error Param Leads to DoS

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-06-02 · updated 2026-07-22
• Weakness: CWE-352

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 products

• Gitlawb openclaude: before 0.5.1 — fixed in 0.5.1

How to fix

Upgrade to a fixed version: Gitlawb openclaude 0.5.1. Check the vendor advisory for mitigations.

References

• https://github.com/Gitlawb/openclaude/commit/739b8d1f40fde0e401a5cbd2b9a55d88bd5124ad
• https://github.com/Gitlawb/openclaude/releases/tag/v0.5.1
• https://github.com/Gitlawb/openclaude/security/advisories/GHSA-c73c-x77g-854r
• https://github.com/Gitlawb/openclaude/security/advisories/GHSA-c73c-x77g-854r

Get alerted when CVE-2026-42073 or the next vulnerability affects your stack