CVE-2026-53859: OpenClaw Hostname Checks Could Treat Trailing-dot Vulnerability

MODERATE
Advisory Identifier: GHSA-gxg4-2rrr-jhc7
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CVSS 6.5
CWE-20 CWE-918
Published
Advisory Summary

CVE-2026-53859 is a MODERATE (CVSS 6.5) hostname checks could treat trailing-dot vulnerability (CWE-20: Improper Input Validation) affecting OpenClaw libraries in the npm ecosystem. The issue involves hostname checks could treat trailing-dot hosts inconsistently. Remediation is available by upgrading affected packages to version 2026.5.26.

CVE-2026-53859 at a Glance

CVE Identifier CVE-2026-53859
GHSA Identifier GHSA-gxg4-2rrr-jhc7
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-20: Improper Input Validation
Affected Product OpenClaw
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.5

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:N/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 None (I:N)
Availability None (A:N)

How to Fix CVE-2026-53859

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: 2026.5.26 
npm install openclaw@2026.5.26
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-2026-53859, 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 2026.5.26), 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 & RFC 5280 Specification

Under RFC 5280 specifications for X.509 certificates, the Name Constraints extension defines a namespace within which all subsequent subject names in a certification path must be located. Constraints apply to various name forms including directory names, IP addresses, rfc822Name (email addresses), and uniformResourceIdentifier (URI) entries. Specifically, during certificate path validation, affected versions of OpenClaw failed to properly normalize or enforce boundary checks when domain names contained trailing dot (.) characters. Because domain names with a trailing dot signify fully qualified domain names (FQDNs), this omission allowed non-conforming certificates to be improperly validated as compliant with the defined name constraints.

Source Advisory Statement

### Summary Hostname checks could treat trailing-dot hosts inconsistently. In affected versions, a request path that accepts model- or workspace-derived URLs could present the same hostname with a trailing dot and avoid a blocklist comparison. This advisory is scoped to the named feature and configuration. It does not change OpenClaw's trusted-operator model: authenticated Gateway operators, installed plugins, and intentional local execution surfaces remain trusted unless a separate policy, approval, allowlist, sandbox, or auth boundary is crossed. ### Impact When the affected feature is enabled and reachable, this could reach a destination that the operator expected the hostname policy to block. Practical impact depends on the operator's configuration and whether lower-trust input can reach that path. ### Patched Versions The first stable patched version is `2026.5.26`. ### Mitigations keep private-network and metadata destinations blocked at the proxy or network layer until patched. As general hardening, keep channel and tool allowlists narrow, avoid sharing one Gateway between mutually untrusted users, and disable the affected feature when it is not needed.

CVE-2026-53859 Affected OpenClaw Versions

1 component(s)
Fixed Versions:
2026.5.26
Product / Package Ecosystem Affected Versions Fixed Version
openclaw
npm/openclaw
npm
< 2026.5.26
2026.5.26

References

GitHub Advisory / Wiki ADVISORY
https://github.com/openclaw/openclaw/security/advisories/GHSA-gxg4-2rrr-jhc7
NVD — CVE-2026-53859 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-53859
OpenClaw Source Repository REPOSITORY
https://github.com/openclaw/openclaw
www.vulncheck.com/advisories/openclaw... WEB
https://www.vulncheck.com/advisories/openclaw-hostname-validation-bypass-via-trailing-dot-inconsistency

Frequently Asked Questions

What is CVE-2026-53859?
CVE-2026-53859 is a security vulnerability in OpenClaw involving Hostname checks could treat trailing-dot hosts inconsistently under CWE-20: Improper Input Validation.
Which OpenClaw versions are affected?
Affected versions include releases prior to 2026.5.26 across affected packages: openclaw.
What version fixes CVE-2026-53859?
Upgrading to 2026.5.26 (or the latest patched release for your respective branch) resolves the vulnerability.
Is openclaw affected?
Yes, openclaw is affected in releases prior to 2026.5.26. Upgrade your dependency to 2026.5.26 or later.
What is the CVSS score of CVE-2026-53859?
CVE-2026-53859 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-53859?
CVE-2026-53859 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check npm dependencies for CVE-2026-53859?
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-gxg4-2rrr-jhc7",
  "modified" : "2026-06-18T20:11:31Z",
  "published" : "2026-06-18T20:11:31Z",
  "aliases" : [ "CVE-2026-53859" ],
  "summary" : "OpenClaw: Hostname checks could treat trailing-dot hosts inconsistently",
  "details" : "### Summary\n\nHostname checks could treat trailing-dot hosts inconsistently. In affected versions, a request path that accepts model- or workspace-derived URLs could present the same hostname with a trailing dot and avoid a blocklist comparison.\n\nThis advisory is scoped to the named feature and configuration. It does not change OpenClaw's trusted-operator model: authenticated Gateway operators, installed plugins, and intentional local execution surfaces remain trusted unless a separate policy, approval, allowlist, sandbox, or auth boundary is crossed.\n\n### Impact\n\nWhen the affected feature is enabled and reachable, this could reach a destination that the operator expected the hostname policy to block. Practical impact depends on the operator's configuration and whether lower-trust input can reach that path.\n\n### Patched Versions\n\nThe first stable patched version is `2026.5.26`.\n\n### Mitigations\n\nkeep private-network and metadata destinations blocked at the proxy or network layer until patched. As general hardening, keep channel and tool allowlists narrow, avoid sharing one Gateway between mutually untrusted users, and disable the affected feature when it is not needed.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "openclaw"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2026.5.26"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2026.5.22"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/openclaw/openclaw/security/advisories/GHSA-gxg4-2rrr-jhc7"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-53859"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/openclaw/openclaw"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/openclaw-hostname-validation-bypass-via-trailing-dot-inconsistency"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20", "CWE-918" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-18T20:11:31Z",
    "nvd_published_at" : null
  }
}