CVE-2025-65099: anthropic claude_code Code Injection

Vulnerability summary

CVE-2025-65099 is a critical (CVSS 9.8) Code Injection vulnerability in anthropic claude_code. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 44.8% of scored vulnerabilities.

Timeline

1. 19-11-2025
   PublishedVulnerability first disclosed.
2. 20-11-2025
   Last modifiedVulnerability information updated.

Description

Claude Code is an agentic coding tool. Prior to version 1.0.39, when running on a machine with Yarn 3.0 or above, Claude Code could have been tricked to execute code contained in a project via yarn plugins before the user accepted the startup trust dialog. Exploiting this would have required a user to start Claude Code in an untrusted directory and to be using Yarn 3.0 or above. This issue has been patched in version 1.0.39.

• CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.