CVE-2026-53840Network attack vector

Credential disclosure via cross-origin redirect header forwarding

Published Jun 16, 2026 · Updated Jun 16, 2026

Information disclosure in OpenClaw before 2026.5.12 allows remote attackers to steal configured MCP headers through cross-origin redirects. The Streamable HTTP client follows an endpoint-supplied cross-origin redirect while retaining operator-configured custom headers for the redirected request. Exploitation requires sensitive headers on a Streamable HTTP MCP server and an endpoint that is malicious, compromised, or able to redirect across origins.

CVSS severity6.0
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in OpenClaw before 2026.5.12 allows remote attackers to steal configured MCP headers through cross-origin redirects. The Streamable HTTP client follows an endpoint-supplied cross-origin redirect while retaining operator-configured custom headers for the redirected request. Exploitation requires sensitive headers on a Streamable HTTP MCP server and an endpoint that is malicious, compromised, or able to redirect across origins.

The record

CVE
CVE-2026-53840
Published
Jun 16, 2026
Updated
Jun 16, 2026
Vendor
OpenClaw Foundation
Product
OpenClaw
Classifications
CWE-522, CWE-200, T1528
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Jun 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2026.5.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

OpenClaw Foundation · OpenClawversion=0 <2026.5.12

Published CVSS scores

6.0VulnCheckCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
7.1GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-522Insufficiently Protected Credentials
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1528Steal Application Access Token

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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