A bug hunter just pocketed $90,000 for finding a way to run arbitrary code on one of Google's own servers.
Security researcher Simon Koeck discovered a remote code execution vulnerability in Google's developer site infrastructure. The bug stemmed from how the backend handled Flask session cookies: instead of relying on the framework's default signed, tamper-proof serializer, the service deserialized session data using Python's pickle module. Pickle is explicitly documented as unsafe for untrusted input because unpickling a crafted object graph can execute arbitrary code. Koeck crafted a malicious session payload, got Google's server to deserialize it, and achieved code execution - a finding serious enough that Google's bug bounty program paid out $90,000.
Pickle-based deserialization bugs are one of the oldest tricks in the Python security playbook, yet they keep surfacing in production systems, even ones run by a company with Google's security resources. It's a reminder that bug classes don't retire just because they're well-documented - they retire when engineering teams stop reaching for convenient-but-dangerous defaults.
Chalk it up as another entry in the long, embarrassing list of 'don't pickle untrusted data' incidents - a rule that's been in Python's own docs for over a decade and still gets ignored.