CVE-2026-53840

HIGH 7.1

OpenClaw < 2026.5.12 - Custom Header Leakage via MCP Streamable HTTP Cross-Origin Redirects

CVSS Score

7.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-522
Vendor	openclaw
Product	openclaw
Published	Jun 16, 2026
Last Updated	Jun 16, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

Low

Availability

None

Affected Versions

OpenClaw / OpenClaw

0 < 2026.5.12

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwh vulncheck.com: https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirects

Credits

🔍 Edward-x (@YLChen-007)