CVE-2026-35603: Claude Code Insecure System-Wide Configuration Loading Enables Vulnerability

MODERATE
Advisory Identifier: GHSA-5cwg-9f6j-9jvx
Share
CVSS 7.3
CWE-426
Published
Advisory Summary

CVE-2026-35603 is a MODERATE (CVSS 7.3) insecure system-wide configuration loading enables vulnerability (CWE-426: Untrusted Search Path) affecting Claude Code libraries in the npm ecosystem. The issue involves insecure system-wide configuration loading enables local privilege escalation on windows. Remediation is available by upgrading affected packages to version 2.1.75.

CVE-2026-35603 at a Glance

CVE Identifier CVE-2026-35603
GHSA Identifier GHSA-5cwg-9f6j-9jvx
Severity MODERATE
CVSS v3.1 Base Score 7.3
CWE Classification CWE-426: Untrusted Search Path
Affected Product Claude Code
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.3

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

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-35603

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

@anthropic-ai/claude-code fixed: 2.1.75 
npm install @anthropic-ai/claude-code@2.1.75
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 @anthropic-ai/claude-code

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-35603, inspect your project dependencies using npm:

npm ls @anthropic-ai/claude-code

Analyze the terminal output to locate any version of Claude Code in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.1.75), your application is affected.

Note: The npm ls @anthropic-ai/claude-code 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-426: Untrusted Search Path, where the product searches for critical resources using an externally-supplied search path that can point to resources that are not under the product's direct control. In Claude Code, 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

On Windows, Claude Code loaded system-wide default configuration from `C:\ProgramData\ClaudeCode\managed-settings.json` without validating directory ownership or access permissions. Because the `ProgramData` directory is writable by non-administrative users by default and the `ClaudeCode` subdirectory was not pre-created or access-restricted, a low-privileged local user could create this directory and place a malicious configuration file that would be automatically loaded for any user launching Claude Code on the same machine. Exploiting this would have required a shared multi-user Windows system and a victim user to launch Claude Code after the malicious configuration was placed. Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version. Thank you to hackerone.com/edbr for reporting this issue.

CVE-2026-35603 Affected Claude Code Versions

1 component(s)
Fixed Versions:
2.1.75
Product / Package Ecosystem Affected Versions Fixed Version
@anthropic-ai/claude-code
npm/@anthropic-ai/claude-code
npm
< 2.1.75
2.1.75

References

GitHub Advisory / Wiki ADVISORY
https://github.com/anthropics/claude-code/security/advisories/GHSA-5cwg-9f6j-9jvx
NVD — CVE-2026-35603 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35603
Claude Code Source Repository REPOSITORY
https://github.com/anthropics/claude-code

Frequently Asked Questions

What is CVE-2026-35603?
CVE-2026-35603 is a security vulnerability in Claude Code involving Insecure System-Wide Configuration Loading Enables Local Privilege Escalation on Windows under CWE-426: Untrusted Search Path.
Which Claude Code versions are affected?
Affected versions include releases prior to 2.1.75 across affected packages: @anthropic-ai/claude-code.
What version fixes CVE-2026-35603?
Upgrading to 2.1.75 (or the latest patched release for your respective branch) resolves the vulnerability.
Is @anthropic-ai/claude-code affected?
Yes, @anthropic-ai/claude-code is affected in releases prior to 2.1.75. Upgrade your dependency to 2.1.75 or later.
What is the CVSS score of CVE-2026-35603?
CVE-2026-35603 has a CVSS v3.1 base score of 7.3 (MODERATE) with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-35603?
CVE-2026-35603 is classified under CWE-426: Untrusted Search Path (The product searches for critical resources using an externally-supplied search path that can point to resources that are not under the product's direct control.).
How can I check npm dependencies for CVE-2026-35603?
Run the dependency tree command: 'npm ls @anthropic-ai/claude-code'. 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-5cwg-9f6j-9jvx",
  "modified" : "2026-04-27T16:21:55Z",
  "published" : "2026-04-17T22:19:38Z",
  "aliases" : [ "CVE-2026-35603" ],
  "summary" : "Claude Code: Insecure System-Wide Configuration Loading Enables Local Privilege Escalation on Windows",
  "details" : "On Windows, Claude Code loaded system-wide default configuration from `C:\\ProgramData\\ClaudeCode\\managed-settings.json` without validating directory ownership or access permissions. Because the `ProgramData` directory is writable by non-administrative users by default and the `ClaudeCode` subdirectory was not pre-created or access-restricted, a low-privileged local user could create this directory and place a malicious configuration file that would be automatically loaded for any user launching Claude Code on the same machine. Exploiting this would have required a shared multi-user Windows system and a victim user to launch Claude Code after the malicious configuration was placed.\n\nUsers on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version.\n\nThank you to hackerone.com/edbr for reporting this issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@anthropic-ai/claude-code"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.75"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/claude-code/security/advisories/GHSA-5cwg-9f6j-9jvx"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-35603"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/anthropics/claude-code"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-426" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-17T22:19:38Z",
    "nvd_published_at" : "2026-04-17T21:16:33Z"
  }
}