WhatsApp Deploys Rust-Based Media Parser to Block Malware on 3 Billion Devices

WhatsApp has rewritten its media handling library in Rust, replacing 160,000 lines of C++ with 90,000 lines of memory-safe code for 3 billion devices. The rollout, part of a system called Kaleidoscope, uses differential fuzzing to ensure bug-for-bug compatibility. The move mirrors a decade-long industry shift toward memory safety, tracing back to Mozilla’s first Rust MP4 parser deployment in 2016.

By Steef-Jan Wiggers