CVE-2026-53840: OpenClaw MCP Streamable HTTP Redirects Could Vulnerability

HIGH
Advisory Identifier: GHSA-rjxq-qqhf-8hwh
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CVSS 7.1
CWE-200
Published
Advisory Summary

CVE-2026-53840 is a HIGH (CVSS 7.1) mcp streamable http redirects could vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting OpenClaw libraries in the npm ecosystem. The issue involves mcp streamable http redirects could forward configured custom headers to another origin. Remediation is available by upgrading affected packages to version 2026.5.12.

CVE-2026-53840 at a Glance

CVE Identifier CVE-2026-53840
GHSA Identifier GHSA-rjxq-qqhf-8hwh
Severity HIGH
CVSS v3.1 Base Score 7.1
CWE Classification CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Affected Product OpenClaw
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-53840

To remediate this vulnerability, upgrade all affected OpenClaw dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

openclaw fixed: 2026.5.12 
npm install openclaw@2026.5.12
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls openclaw

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-53840, inspect your project dependencies using npm:

npm ls openclaw

Analyze the terminal output to locate any version of OpenClaw in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2026.5.12), your application is affected.

Note: The npm ls openclaw command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. In OpenClaw, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary OpenClaw supports remote MCP Streamable HTTP servers with operator-configured custom headers. In affected releases, those headers could be forwarded when the MCP endpoint responded with a cross-origin redirect. This issue is limited to configured MCP Streamable HTTP servers that use custom headers. It does not expose unrelated OpenClaw credentials. ### Affected configurations This affects deployments where an MCP server is configured with: - `transportType: "streamable-http"` - sensitive custom headers under `mcp.servers.*.headers` - an MCP endpoint that is malicious, compromised, or able to redirect to another origin ### Impact Custom MCP headers, such as API keys or tenant-routing headers, could be sent to the redirect target. The exposed credential scope depends on the header the operator configured for that MCP server. ### Patched Versions The first stable patched version is `2026.5.12`. ### Mitigations Upgrade to `openclaw@2026.5.8` or later. Before upgrading, avoid custom MCP headers with servers you do not fully trust, and rotate any MCP-specific credentials that may have been exposed by a redirecting endpoint.

CVE-2026-53840 Affected OpenClaw Versions

1 component(s)
Fixed Versions:
2026.5.12
Product / Package Ecosystem Affected Versions Fixed Version
openclaw
npm/openclaw
npm
< 2026.5.12
2026.5.12

References

GitHub Advisory / Wiki ADVISORY
https://github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwh
NVD — CVE-2026-53840 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-53840
OpenClaw Source Repository REPOSITORY
https://github.com/openclaw/openclaw
www.vulncheck.com/advisories/openclaw... WEB
https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirects

Frequently Asked Questions

What is CVE-2026-53840?
CVE-2026-53840 is a security vulnerability in OpenClaw involving MCP Streamable HTTP redirects could forward configured custom headers to another origin under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor.
Which OpenClaw versions are affected?
Affected versions include releases prior to 2026.5.12 across affected packages: openclaw.
What version fixes CVE-2026-53840?
Upgrading to 2026.5.12 (or the latest patched release for your respective branch) resolves the vulnerability.
Is openclaw affected?
Yes, openclaw is affected in releases prior to 2026.5.12. Upgrade your dependency to 2026.5.12 or later.
What is the CVSS score of CVE-2026-53840?
CVE-2026-53840 has a CVSS v3.1 base score of 7.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N.
What CWE is associated with CVE-2026-53840?
CVE-2026-53840 is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor (The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.).
How can I check npm dependencies for CVE-2026-53840?
Run the dependency tree command: 'npm ls openclaw'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rjxq-qqhf-8hwh",
  "modified" : "2026-06-17T17:55:07Z",
  "published" : "2026-06-17T17:55:06Z",
  "aliases" : [ "CVE-2026-53840" ],
  "summary" : "OpenClaw: MCP Streamable HTTP redirects could forward configured custom headers to another origin",
  "details" : "### Summary\n\nOpenClaw supports remote MCP Streamable HTTP servers with operator-configured custom headers. In affected releases, those headers could be forwarded when the MCP endpoint responded with a cross-origin redirect.\n\nThis issue is limited to configured MCP Streamable HTTP servers that use custom headers. It does not expose unrelated OpenClaw credentials.\n\n### Affected configurations\n\nThis affects deployments where an MCP server is configured with:\n\n- `transportType: \"streamable-http\"`\n- sensitive custom headers under `mcp.servers.*.headers`\n- an MCP endpoint that is malicious, compromised, or able to redirect to another origin\n\n### Impact\n\nCustom MCP headers, such as API keys or tenant-routing headers, could be sent to the redirect target. The exposed credential scope depends on the header the operator configured for that MCP server.\n\n### Patched Versions\n\nThe first stable patched version is `2026.5.12`.\n\n### Mitigations\n\nUpgrade to `openclaw@2026.5.8` or later. Before upgrading, avoid custom MCP headers with servers you do not fully trust, and rotate any MCP-specific credentials that may have been exposed by a redirecting endpoint.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "openclaw"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2026.5.12"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwh"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-53840"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/openclaw/openclaw"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirects"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-17T17:55:06Z",
    "nvd_published_at" : null
  }
}