SINGAPORE—China said Wednesday that it has found “security backdoor vulnerabilities” in Anthropic’s popular Claude Code, stepping up tensions in the race with the U.S. for artificial-intelligence supremacy.Since February, Anthropic has accused Alibaba and several other Chinese AI labs of illicitly distilling its models-the practice of training a new model on the outputs of another.Several versions of the American coding tool, released between April and June, “can send sensitive information such as user location and identity to remote servers without the user’s consent due to a built-in monitoring mechanism,” China’s National Vulnerability DataBase, a government-run cybersecurity platform, said in a statement.The...