bughunters.google.comwriteup

https://bughunters.google.com/blog/pagebreak-real-world-findings?utm_source=tldrsec.com&utm_medium=newsletter&utm_campaign=tl-dr-sec-348-google-s-pagebreak-scanner-perplexity-s-agent-security-tool-defending-agentically

Google's Product Security team describes three high-severity bugs found by PageBreak, an internal LLM-agent scanner that validates findings by running payloads against live environments. The cases are cache poisoning on apis.google.com (an unkeyed `extra_path` injected into cached JS), XSS on admin.google.com where the agent bypassed the `sig` check by getting the authorize endpoint to sign a `javascript:` URI, and a UXSS in the Tag Assistant extension via a weak `onConnectExternal` origin check and nonce exfiltration. It shows what agentic, deterministically verified scanning can find in well-reviewed targets.