{"id":"CVE-2026-42073","aliases":["GHSA-c73c-x77g-854r"],"url":"https://o3.security/vulnerability/CVE-2026-42073","summary":"OpenClaude's MCP OAuth Callback: State Check Bypass via error Param Leads to DoS","details":"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.","published":"2026-06-02T15:38:53.435Z","modified":"2026-07-24T03:57:03.318239421Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"@gitlawb/openclaude","fixedVersion":"0.5.1"}],"fix":{"url":"https://github.com/Gitlawb/openclaude/commit/739b8d1f40fde0e401a5cbd2b9a55d88bd5124ad","label":"Gitlawb/openclaude@739b8d1"},"references":[{"type":"WEB","url":"https://github.com/Gitlawb/openclaude/releases/tag/v0.5.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42073.json"},{"type":"ADVISORY","url":"https://github.com/Gitlawb/openclaude/security/advisories/GHSA-c73c-x77g-854r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42073"},{"type":"FIX","url":"https://github.com/Gitlawb/openclaude/commit/739b8d1f40fde0e401a5cbd2b9a55d88bd5124ad"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-24T03:57:03.318239421Z"}}