CVE-2026-42420: OpenClaw Multiple Code Paths Missing Base64 Vulnerability

MODERATE
Advisory Identifier: GHSA-ccx3-fw7q-rr2r
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CVSS 4.3
CWE-770
Published
Advisory Summary

CVE-2026-42420 is a MODERATE (CVSS 4.3) multiple code paths missing base64 vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting OpenClaw libraries in the npm ecosystem. The issue involves multiple code paths missing base64 pre-allocation size checks. Remediation is available by upgrading affected packages to version 2026.4.8.

CVE-2026-42420 at a Glance

CVE Identifier CVE-2026-42420
GHSA Identifier GHSA-ccx3-fw7q-rr2r
Severity MODERATE
CVSS v3.1 Base Score 4.3
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product OpenClaw
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 4.3

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:N/I:N/A:L).

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 None (C:N)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-42420

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: 2026.4.8 
npm install openclaw@2026.4.8
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-2026-42420, 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 2026.4.8), 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-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. 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

## Impact Multiple Code Paths Missing Base64 Pre-Allocation Size Checks. Several base64 decode paths could allocate before enforcing decoded-size limits. OpenClaw is a user-controlled local assistant. This advisory is scoped to the OpenClaw trust model and does not assume a multi-tenant service boundary. ## Affected Packages / Versions - Package: `openclaw` (npm) - Affected versions: `<=v2026.4.2` - Patched versions: `2026.4.8` ## Fix The issue was fixed on `main` and is available in the patched npm version listed above. The verified fixed tree is commit `d7c3210cd6f5fdfdc1beff4c9541673e814354d5`. ## Verification The fix was re-checked against `main` before publication, including targeted regression tests for the affected security boundary. ## Credits Thanks @zsxsoft and @KeenSecurityLab for reporting.

CVE-2026-42420 Affected OpenClaw Versions

1 component(s)
Fixed Versions:
2026.4.8
Product / Package Ecosystem Affected Versions Fixed Version
openclaw
npm/openclaw
npm
< 2026.4.8
2026.4.8

References

GitHub Advisory / Wiki ADVISORY
https://github.com/openclaw/openclaw/security/advisories/GHSA-ccx3-fw7q-rr2r
NVD — CVE-2026-42420 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42420
Security Fix Commit FIX COMMIT
https://github.com/openclaw/openclaw/commit/d7c3210cd6f5fdfdc1beff4c9541673e814354d5
OpenClaw Source Repository REPOSITORY
https://github.com/openclaw/openclaw
www.vulncheck.com/advisories/openclaw... WEB
https://www.vulncheck.com/advisories/openclaw-improper-base64-decoding-size-validation

Frequently Asked Questions

What is CVE-2026-42420?
CVE-2026-42420 is a security vulnerability in OpenClaw involving Multiple Code Paths Missing Base64 Pre-Allocation Size Checks under CWE-770: Allocation of Resources Without Limits or Throttling.
Which OpenClaw versions are affected?
Affected versions include releases prior to 2026.4.8 across affected packages: openclaw.
What version fixes CVE-2026-42420?
Upgrading to 2026.4.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is openclaw affected?
Yes, openclaw is affected in releases prior to 2026.4.8. Upgrade your dependency to 2026.4.8 or later.
What is the CVSS score of CVE-2026-42420?
CVE-2026-42420 has a CVSS v3.1 base score of 4.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2026-42420?
CVE-2026-42420 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check npm dependencies for CVE-2026-42420?
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-ccx3-fw7q-rr2r",
  "modified" : "2026-05-06T02:41:29Z",
  "published" : "2026-04-09T17:37:20Z",
  "aliases" : [ "CVE-2026-42420" ],
  "summary" : "OpenClaw: Multiple Code Paths Missing Base64 Pre-Allocation Size Checks",
  "details" : "## Impact\n\nMultiple Code Paths Missing Base64 Pre-Allocation Size Checks.\n\nSeveral base64 decode paths could allocate before enforcing decoded-size limits.\n\nOpenClaw is a user-controlled local assistant. This advisory is scoped to the OpenClaw trust model and does not assume a multi-tenant service boundary.\n\n## Affected Packages / Versions\n\n- Package: `openclaw` (npm)\n- Affected versions: `<=v2026.4.2`\n- Patched versions: `2026.4.8`\n\n## Fix\n\nThe issue was fixed on `main` and is available in the patched npm version listed above. The verified fixed tree is commit `d7c3210cd6f5fdfdc1beff4c9541673e814354d5`.\n\n## Verification\n\nThe fix was re-checked against `main` before publication, including targeted regression tests for the affected security boundary.\n\n## Credits\n\nThanks @zsxsoft and @KeenSecurityLab for reporting.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "openclaw"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2026.4.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/openclaw/openclaw/security/advisories/GHSA-ccx3-fw7q-rr2r"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-42420"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openclaw/openclaw/commit/d7c3210cd6f5fdfdc1beff4c9541673e814354d5"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/openclaw/openclaw"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/openclaw-improper-base64-decoding-size-validation"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-09T17:37:20Z",
    "nvd_published_at" : "2026-04-28T19:37:45Z"
  }
}