Anthropic's Claude Code runs code to test if it is safe – which might be a big mistake

App security outfit Checkmarx says automated reviews in Anthropic's Claude Code can catch some bugs but miss others – and sometimes create new risks by executing code while testing it. Anthropic introduced automated security reviews in Claude Code last month, promising to ensure that "no code reaches production without a baseline security review." The AI-driven review checks for common vulnerability patterns including authentication and authorization flaws, insecure data handling, dependency vulnerabilities, and SQL injection. Checkmarx reported that the /security-review command in Claude Code was successful in finding simple vulnerabilities such as XSS (cross-site scripting) and even an authorization bypass issue that many static analysis tools might miss. However, it was defeated by a remote code execution vulnerability using the Python data analysis library pandas, and wrongly concluded it was a false positive. A more difficult area is when code is crafted to mislead AI inspection. The researchers did this with a function called "sanitize," complete with a comment describing how it looked for unsafe or invalid input, which actually ran an obviously unsafe process. This passed the Claude Code security review, which declared "security impact: none." Another problem is that the Claude Code security review generates and executes its own test cases. The potential snag here is that "simply reviewing code can actually add new risk to your organization," the researchers said. The ...