{"id":"CVE-2026-53840","title":"OpenClaw: MCP Streamable HTTP redirects could forward configured custom headers to another origin","summary":"OpenClaw: MCP Streamable HTTP redirects could forward configured custom headers to another origin","severity":"high","cvss":7.1,"cwe":["CWE-200"],"vendor":"openclaw","product":"openclaw","ecosystem":"npm","affected":["openclaw < 2026.5.12"],"patched":["openclaw 2026.5.12"],"published":"2026-06-17","updated":"2026-06-17","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-rjxq-qqhf-8hwh","references":[{"url":"https://github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwh"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53840"},{"url":"https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirects"},{"url":"https://github.com/advisories/GHSA-rjxq-qqhf-8hwh"}],"tags":["ghsa","npm"],"epss":0.00223,"epssPercentile":0.13176,"ingestedAt":"2026-06-29T14:31:47.235Z","slug":"CVE-2026-53840","body":"## Overview\n\n### Summary\n\nOpenClaw supports remote MCP Streamable HTTP servers with operator-configured custom headers. In affected releases, those headers could be forwarded when the MCP endpoint responded with a cross-origin redirect.\n\nThis issue is limited to configured MCP Streamable HTTP servers that use custom headers. It does not expose unrelated OpenClaw credentials.\n\n### Affected configurations\n\nThis affects deployments where an MCP server is configured with:\n\n- `transportType: \"streamable-http\"`\n- sensitive custom headers under `mcp.servers.*.headers`\n- an MCP endpoint that is malicious, compromised, or able to redirect to another origin\n\n### Impact\n\nCustom MCP headers, such as API keys or tenant-routing headers, could be sent to the redirect target. The exposed credential scope depends on the header the operator configured for that MCP server.\n\n### Patched Versions\n\nThe first stable patched version is `2026.5.12`.\n\n### Mitigations\n\nUpgrade to `openclaw@2026.5.8` or later. Before upgrading, avoid custom MCP headers with servers you do not fully trust, and rotate any MCP-specific credentials that may have been exposed by a redirecting endpoint.\n\n## Affected packages\n\n- `openclaw < 2026.5.12`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `openclaw 2026.5.12`","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}