CVE-2026-53840CWE-522

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

Medium · published June 16, 2026

CVSS v4.0
6.0
EPSS
0%
Percentile
22.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.0 · MEDIUM
Vector
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
EPSS
0.00310 · 22.6th percentile
Weakness
CWE-522 · Insufficiently Protected Credentials
Published
2026-06-16T18:04Z
EPSS history
Timeline
  • 16 JUN 18:04Z
    OpenClaw < 2026.5.12 - Custom Header Leakage via MCP Streamable HTTP Cross-Origin Redirects
    cvelistv5