CVE-2026-53840

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

State: Published
Severity: 6.0 Medium
Published: Jun 16, 2026
Updated: Jun 16, 2026
Reserved: Jun 10, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	6.0 Medium	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N	VulnCheck
3.1	7.1 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N	VulnCheck

Weaknesses

CWE-522 Insufficiently Protected Credentials

Affected Products

Product	Versions
OpenClawOpenClaw	before 2026.5.12Affected 2026.5.12Not affected

References

GitHub Security Advisory (GHSA-rjxq-qqhf-8hwh)vendor-advisory
VulnCheck Advisory: OpenClaw < 2026.5.12 - Custom Header Leakage via MCP Streamable HTTP Cross-Origin Redirectsthird-party-advisory

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