What’s Vulnerable › Vulnerabilities

CVE-2026-53840: OpenClaw < 2026.5.12 - Custom Header Leakage via MCP Streamable HTTP Cross-Origin Redirects

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-16 · updated 2026-06-17
• Weakness: CWE-522

Description

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.

Affected products

• OpenClaw: before 2026.5.12; 2026.5.12-beta1, 2026.5.12-beta2, 2026.5.12-beta3, 2026.5.12-beta4, 2026.5.12-beta5, 2026.5.12-beta6 (+2) — fixed in 2026.5.12

How to fix

Upgrade to a fixed version: OpenClaw 2026.5.12. Check the vendor advisory for mitigations.

References

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

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