{"id":"CVE-2026-53840","aliases":["GHSA-rjxq-qqhf-8hwh"],"url":"https://o3.security/vulnerability/CVE-2026-53840","summary":"OpenClaw < 2026.5.12 - Custom Header Leakage via MCP Streamable HTTP Cross-Origin Redirects","details":"OpenClaw before 2026.5.12 contains an information disclosure vulnerability in streamable-http MCP servers that forwards operator-configured custom headers during cross-origin redirects. Attackers controlling or compromising an MCP endpoint can redirect requests to exfiltrate sensitive headers like API keys or tenant-routing credentials to attacker-controlled origins.","published":"2026-06-16T18:04:53.345Z","modified":"2026-08-09T03:46:34.012240364Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"openclaw","fixedVersion":"2026.5.12"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53840.json"},{"type":"ADVISORY","url":"https://github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwh"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53840"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirects"},{"type":"PACKAGE","url":"https://github.com/openclaw/openclaw"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-09T03:46:34.012240364Z"}}