CVE-2026-53840
highpriority · track · 0EPSS 0.002 · 13 %ileDEEUUSEPSS · scored 2026-10-28
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–high · 2.3–7.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (5)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1738OpenClaw: Mehrere SchwachstellenDeutsch2026-05-28csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in OpenClaw ausnutzen, um Sicherheitsmechanismen zu umgehen, erhöhte Berechtigungen zu erlangen, Informationen offenzulegen, Konfigurationen zu manipulieren, beliebige Befehle oder Code auszuführen sowie interne Systeme über SSRF anzugreifen.
- GHSA-rjxq-qqhf-8hwhOpenClaw: MCP Streamable HTTP redirects could forward configured custom headers to another origin2026-06-17ghsa · osvUS
### Summary 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. ### Affected configurations This affects deployments where an MCP server is configured with: - `transportType: "streamable-http"` - sensitive custom headers under `mcp.servers.*.headers` - an MCP endpoint that is malicious, compromised, or able to redirect to another origin ### Impact Custom 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. ### Patched Versions The first stable patched version is `2026.5.12`. ### Mitigations Upgrade 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.
also known as (4)
Other names and identifiers for this entity.
sources
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references (7)
External citations — patches, advisories, analysis.
- https://github.com/openclaw/openclaw/releasesPatchcnnvd
- https://github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwhcnnvd
- https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirectscnnvd
- https://github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwhenisa_euvd
- https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirectsenisa_euvd
- https://github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwhVendor Advisorynvd
- https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirectsThird Party Advisorynvd
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