CVE-2026-25725: @anthropic ai/claude code Claude Code Has Sandbox Escape Vulnerability

HIGH
Advisory Identifier: GHSA-ff64-7w26-62rf
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CWE-668 CWE-501
Published
Advisory Summary

CVE-2026-25725 is a HIGH claude code has sandbox escape vulnerability (CWE-668: Exposure of Resource to Wrong Sphere) affecting @anthropic ai/claude code libraries in the npm ecosystem. The issue involves claude code has sandbox escape via persistent configuration injection in settings.json. Remediation is available by upgrading affected packages to version 2.1.2.

CVE-2026-25725 at a Glance

CVE Identifier CVE-2026-25725
GHSA Identifier GHSA-ff64-7w26-62rf
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-668: Exposure of Resource to Wrong Sphere
Affected Product @anthropic ai/claude code
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-25725

To remediate this vulnerability, upgrade all affected @anthropic ai/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: 2.1.2 
npm install @anthropic-ai/claude-code@2.1.2
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-2026-25725, inspect your project dependencies using npm:

npm ls @anthropic-ai/claude-code

Analyze the terminal output to locate any version of @anthropic ai/claude code in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.1.2), 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-668: Exposure of Resource to Wrong Sphere, where the product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource. In @anthropic ai/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

Claude Code's bubblewrap sandboxing mechanism failed to properly protect the .claude/settings.json configuration file when it did not exist at startup. While the parent directory was mounted as writable and .claude/settings.local.json was explicitly protected with read-only constraints, settings.json was not protected if it was missing. This allowed malicious code running inside the sandbox to create this file and inject persistent hooks (such as SessionStart commands) that would execute with host privileges when Claude Code was restarted. Users on standard Claude Code auto-update received this fix automatically. Users performing manual updates are advised to update to the latest version. Claude Code thanks hackerone.com/edbr for reporting this issue!

CVE-2026-25725 Affected @anthropic ai/claude code Versions

1 component(s)
Fixed Versions:
2.1.2
Product / Package Ecosystem Affected Versions Fixed Version
@anthropic-ai/claude-code
npm/@anthropic-ai/claude-code
npm
< 2.1.2
2.1.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/anthropics/claude-code/security/advisories/GHSA-ff64-7w26-62rf
NVD — CVE-2026-25725 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-25725
@anthropic ai/claude code Source Repository REPOSITORY
https://github.com/anthropics/claude-code

Frequently Asked Questions

What is CVE-2026-25725?
CVE-2026-25725 is a security vulnerability in @anthropic ai/claude code involving Claude Code has Sandbox Escape via Persistent Configuration Injection in settings.json under CWE-668: Exposure of Resource to Wrong Sphere.
Which @anthropic ai/claude code versions are affected?
Affected versions include releases prior to 2.1.2 across affected packages: @anthropic-ai/claude-code.
What version fixes CVE-2026-25725?
Upgrading to 2.1.2 (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 2.1.2. Upgrade your dependency to 2.1.2 or later.
What CWE is associated with CVE-2026-25725?
CVE-2026-25725 is classified under CWE-668: Exposure of Resource to Wrong Sphere (The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.).
How can I check npm dependencies for CVE-2026-25725?
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-ff64-7w26-62rf",
  "modified" : "2026-02-06T19:14:33Z",
  "published" : "2026-02-06T19:14:33Z",
  "aliases" : [ "CVE-2026-25725" ],
  "summary" : "Claude Code has Sandbox Escape via Persistent Configuration Injection in settings.json",
  "details" : "Claude Code's bubblewrap sandboxing mechanism failed to properly protect the .claude/settings.json configuration file when it did not exist at startup. While the parent directory was mounted as writable and .claude/settings.local.json was explicitly protected with read-only constraints, settings.json was not protected if it was missing. This allowed malicious code running inside the sandbox to create this file and inject persistent hooks (such as SessionStart commands) that would execute with host privileges when Claude Code was restarted. \n\nUsers on standard Claude Code auto-update received this fix automatically. Users performing manual updates are advised to update to the latest version.\n\nClaude Code thanks hackerone.com/edbr for reporting this issue!",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/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" : "2.1.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/claude-code/security/advisories/GHSA-ff64-7w26-62rf"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-25725"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/anthropics/claude-code"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-501", "CWE-668" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-06T19:14:33Z",
    "nvd_published_at" : "2026-02-06T18:16:00Z"
  }
}