CVE-2026-42073

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

Published Jun 2, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-c73c-x77g-854r OpenClaude MCP OAuth Callback: State Check Bypass via error Param Leads to DoS
History
Type Values Removed Values Added
CPEs cpe:2.3:a:gitlawb:openclaude:*:*:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Gitlawb
Gitlawb openclaude
Vendors & Products Gitlawb
Gitlawb openclaude
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title OpenClaude's MCP OAuth Callback: State Check Bypass via error Param Leads to DoS
Weaknesses CWE-352
CWE-400
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jun 2, 2026, 5:40 PM
Reserved
Apr 23, 2026, 7:17 PM
Status
Analyzed
Published
Jun 2, 2026, 5:16 PM
Modified
Jul 22, 2026, 7:10 PM