Vulnerability in Openclaw
CVE-2026-53840
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 · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (21.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 21.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Openclaw — versions 0, 2026.5.12
Weakness classification (CWE)
References
- github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwh (vendor-advisory, Vendor Advisory)
- www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-53840?
- CVE-2026-53840 is a high-severity vulnerability in Openclaw, classified under Insufficiently Protected Credentials. CVSS score: 7.1/10. Published 2026-06-16.
- How severe is CVE-2026-53840?
- High severity. CVSS v3 base score is 7.1 out of 10.