A pull request is a proposed code change submitted in a development workflow for review before it is merged into a main branch. It usually includes the code diff plus surrounding text such as descriptions, comments, labels, and review threads. That extra context helps teams discuss the change, but it also expands the attack surface.
In cybersecurity, PRs matter because attackers may abuse the text around code rather than the code itself. Hidden comments, malformed formatting, or social engineering can influence human reviewers and AI tools that ingest repository content. In agentic workflows, a PR can become a command channel if untrusted text is treated like instructions. Defenses include least-privilege repository access, careful separation of data from instructions, human approval for sensitive actions, and logging of tool use. Treat PR comments and metadata as untrusted input, just like any other user-controlled content.