CVE-2026-86063: @anthropic-ai/claude-code Plugin Hash Pin Bypass Vulnerability
Summary
CVE-2026-86063: Claude Code: Plugin Hash Pin Bypass Allows Bypass of Hash Pinning. Affects @anthropic-ai/claude-code versions < 2.1.179. Fixed in 2.1.179. How to fix ↓
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Background
Claude Code is a development tool designed to enhance coding efficiency by integrating various plugins from a marketplace. It allows users to pin specific versions of plugins using commit SHAs to ensure stability and security. However, a vulnerability exists that allows attackers to bypass this hash pinning mechanism, potentially leading to the installation of malicious code.
Vulnerability Detail
The vulnerability arises from the plugin installation process in Claude Code and Claude Desktop, which uses git checkout to verify a marketplace's pinned commit SHA. However, it fails to ensure that the resulting HEAD matches the pinned SHA. An attacker could exploit this by creating a branch named after the pinned SHA, causing the checkout to resolve to the attacker's branch instead of the intended commit. This could lead to the installation of malicious code, posing significant security risks to users who install plugins from compromised repositories.
How To Fix
Latest published version: 2.1.308 as of 23 Oct 2026
npm install @anthropic-ai/claude-code@2.1.308Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2.1.179
This is the first release that contains the fix.
npm install @anthropic-ai/claude-code@2.1.179Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users should avoid installing plugins from untrusted sources or repositories that allow SHA-shaped branch names until they can update to the patched version.
Conclusion
CVE-2026-86063 represents a significant security risk for users of the @anthropic-ai/claude-code package, allowing attackers to bypass hash pinning and install malicious code. Users are strongly advised to update to the latest version to mitigate this risk.
See every vulnerability recorded for @anthropic-ai/claude-code →
FAQ
CVE-2026-86063 is a vulnerability in the @anthropic-ai/claude-code package that allows attackers to bypass hash pinning, potentially leading to the installation of malicious plugins.
If your application uses the affected version of @anthropic-ai/claude-code and installs plugins from untrusted sources, it may inadvertently execute malicious code.
As a temporary measure, refrain from installing plugins from untrusted sources or repositories that permit SHA-shaped branch names.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected by this vulnerability.
The CVSS score for this vulnerability is 7.5, indicating a high severity level.
Related vulnerabilities
Recent vulnerabilities recorded for @anthropic-ai/claude-code.
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