Repository compromise via workflow expression injection

Command injection in serverless-dns before 0.1.31 allows remote attackers to write arbitrary data to its repository via a pull request. The pr.yml pull_request_target workflow expands attacker-controlled clone_url and head_ref expressions directly inside shell commands instead of passing them through environment variables. No repository account is required; the workflow token's write permission lets injected commands alter repository content that end users later execute.