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

What is CVE-2026-53840?

CVE-2026-53840 is a medium-severity vulnerability in Openclaw Openclaw, published on 16 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official 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.

Weakness: CWE-522

Which versions are affected by CVE-2026-53840?

2 open source packages ship an affected version, including openclaw. It affects 1 product.

Products include Openclaw Openclaw.

How do I fix CVE-2026-53840?

Upgrade openclaw to 2026.5.12 or later.

Is CVE-2026-53840 being exploited?

There is no known exploitation of CVE-2026-53840 in the wild and no public exploit code.

Other vulnerabilities in Openclaw Openclaw

• CVE-2026-28363 Security feature bypass in OpenClaw Critical 9.9
• CVE-2026-30741 Code injection in n/a Critical 9.8
• CVE-2026-33579 OpenClaw < 2026.3.28 - Privilege Escalation via Missing Caller Scope Validation in Device Pair Approval Critical 9.4
• CVE-2026-32922 OpenClaw < 2026.3.11 - Privilege Escalation via Unvalidated Scope in device.token.rotate Critical 9.4
• CVE-2026-32978 OpenClaw < 2026.3.11 - Approval Bypass via Unrecognized Script Runners Critical 9.4

All Openclaw Openclaw vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-rjxq-qqhf-8hwh, MINI-fh23-xv78-h6xr.