CVE-2026-53840: OpenClaw: MCP Streamable HTTP redirects could forward configured custom headers to another origin

June 17, 2026

OpenClaw 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.

This issue is limited to configured MCP Streamable HTTP servers that use custom headers. It does not expose unrelated OpenClaw credentials.

References

github.com/advisories/GHSA-rjxq-qqhf-8hwh
github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwh
nvd.nist.gov/vuln/detail/CVE-2026-53840
www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirects

Code Behaviors & Features

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