Starstrike

Achieving Deterministic Prompt Injection Through Client-Side Feedback Loops

Thu, 23 Apr 2026 18:00:00 +0000

About the Author

XSSDoctor is a clinical cardiologist and a well regarded bug bounty hunter. His focus is on frontend vulnerabilities and client-side hacking. He has published research on Javascript deobfuscation and client side path traversal among other topics.

VolumeLeak: Classifier-based Data Exfiltration via Volume Settings

Sat, 21 Feb 2026 18:00:00 +0000

Introduction

About 6 months after PhoneLeak, we participated in another Bugswat Live Hacking Event in Mexico City. Our focus returned again to the tool calls at our disposition in the Gemini Android app, as we felt that there was unfinished business there. More specifically, we realised that because Google’s team had accepted vulnerabilities that involved a mobile app being installed as a prerequisite (albeit with major bounty downgrades), it mean that in theory, any property that was both writeable by Gemini and readable by a mobile app (without excessive permissioning requirements) was a potential attack surface for data exfiltration. This observation proved to be invaluable.

PhoneLeak: Data Exfiltration in Gemini via Phone Call

Mon, 09 Feb 2026 18:00:00 +0000

Introduction

This post describes a data exfiltration vulnerability we found in collaboration with rez0, rhynorater and lupin in Google’s Bugswat Live Hacking Event in Tokyo, Japan in April 2025, which our team won overall. This specific issue was also awarded Most Creative Finding.