BREW-OPENCLAW-CLI-CVE-20… (GHSA-RJXQ-QQHF-8HWH)
Vulnerability from osv_homebrew – Published: 2026-08-13 17:21 – Updated: 2026-11-10 09:00 – Source websiteSummary
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.
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"upstream_fixed_in": "2026.5.12"
},
"package": {
"ecosystem": "Homebrew",
"name": "openclaw-cli",
"purl": "pkg:brew/openclaw-cli"
},
"ranges": [
{
"events": [
{
"introduced": "2026.1.29"
},
{
"fixed": "2026.5.12"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "npm",
"key": "pkg:npm/openclaw@2026.11.2",
"name": "openclaw",
"strategy": "registry",
"subject_version": "2026.11.2"
}
]
},
"details": "### 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.",
"id": "BREW-openclaw-cli-CVE-2026-53840",
"modified": "2026-11-10T09:00:02Z",
"published": "2026-08-13T17:21:32Z",
"references": [
{
"type": "WEB",
"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": "PACKAGE",
"url": "https://github.com/openclaw/openclaw"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirects"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "OpenClaw: MCP Streamable HTTP redirects could forward configured custom headers to another origin",
"upstream": [
"GHSA-rjxq-qqhf-8hwh",
"CVE-2026-53840"
]
}
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Nomenclature
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Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
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