CVE-2026-86063: Claude Code Plugin Hash Pin Bypass Allows Vulnerability

HIGH
Advisory Identifier: GHSA-pq7j-f95f-qfcv
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CWE-829 CWE-494
Published
Advisory Summary

CVE-2026-86063 is a HIGH plugin hash pin bypass allows vulnerability (CWE-829: Inclusion of Functionality from Untrusted Control Sphere) affecting Claude Code libraries in the npm ecosystem. The issue involves plugin hash pin bypass allows bypass of hash pinning. Remediation is available by upgrading affected packages to version 2.1.179.

CVE-2026-86063 at a Glance

CVE Identifier CVE-2026-86063
GHSA Identifier GHSA-pq7j-f95f-qfcv
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-829: Inclusion of Functionality from Untrusted Control Sphere
Affected Product Claude Code
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-86063

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: 2.1.179 
npm install @anthropic-ai/claude-code@2.1.179
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-2026-86063, 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 2.1.179), 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-829: Inclusion of Functionality from Untrusted Control Sphere, where the product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere. 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

The plugin install flow in Claude Code and Claude Desktop checked out a marketplace's pinned commit SHA using `git checkout` without verifying that the resulting HEAD matched the pinned SHA. An attacker controlling a plugin's upstream repository could create a branch named identically to the pinned 40-character SHA, causing the checkout to silently resolve to the attacker's branch tip instead of the reviewed commit, resulting in attacker-controlled code being installed bypassing the pinned hash. Exploitation required a user to install a malicious plugin, pin to a safe hash, and for the plugin source to be hosted on a git host that permitted SHA-shaped branch names. 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 Or Nevo Michrowski of Air Security for reporting this issue.

CVE-2026-86063 Affected Claude Code Versions

1 component(s)
Fixed Versions:
2.1.179
Product / Package Ecosystem Affected Versions Fixed Version
@anthropic-ai/claude-code
npm/@anthropic-ai/claude-code
npm
< 2.1.179
2.1.179

References

GitHub Advisory / Wiki ADVISORY
https://github.com/anthropics/claude-code/security/advisories/GHSA-pq7j-f95f-qfcv
NVD — CVE-2026-86063 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-86063
Claude Code Source Repository REPOSITORY
https://github.com/anthropics/claude-code
Claude Code Release RELEASE
https://github.com/anthropics/claude-code/releases/tag/v2.1.179

Frequently Asked Questions

What is CVE-2026-86063?
CVE-2026-86063 is a security vulnerability in Claude Code involving Plugin Hash Pin Bypass Allows Bypass of Hash Pinning under CWE-829: Inclusion of Functionality from Untrusted Control Sphere.
Which Claude Code versions are affected?
Affected versions include releases prior to 2.1.179 across affected packages: @anthropic-ai/claude-code.
What version fixes CVE-2026-86063?
Upgrading to 2.1.179 (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 2.1.179. Upgrade your dependency to 2.1.179 or later.
What CWE is associated with CVE-2026-86063?
CVE-2026-86063 is classified under CWE-829: Inclusion of Functionality from Untrusted Control Sphere (The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.).
How can I check npm dependencies for CVE-2026-86063?
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-pq7j-f95f-qfcv",
  "modified" : "2026-10-15T20:22:07Z",
  "published" : "2026-10-15T20:22:07Z",
  "aliases" : [ "CVE-2026-86063" ],
  "summary" : "Claude Code: Plugin Hash Pin Bypass Allows Bypass of Hash Pinning",
  "details" : "The plugin install flow in Claude Code and Claude Desktop checked out a marketplace's pinned commit SHA using `git checkout` without verifying that the resulting HEAD matched the pinned SHA. An attacker controlling a plugin's upstream repository could create a branch named identically to the pinned 40-character SHA, causing the checkout to silently resolve to the attacker's branch tip instead of the reviewed commit, resulting in attacker-controlled code being installed bypassing the pinned hash. Exploitation required a user to install a malicious plugin, pin to a safe hash, and for the plugin source to be hosted on a git host that permitted SHA-shaped branch names.\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 Or Nevo Michrowski of Air Security for reporting this issue.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/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" : "2.1.179"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/claude-code/security/advisories/GHSA-pq7j-f95f-qfcv"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-86063"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/anthropics/claude-code"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/claude-code/releases/tag/v2.1.179"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-494", "CWE-829" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-15T20:22:07Z",
    "nvd_published_at" : "2026-10-13T19:21:21Z"
  }
}