January 28, 2026
Rusty? More like trusty
Rust at Scale: An Added Layer of Security for WhatsApp
WhatsApp says Rust will keep your pics safer — cheers, nitpicks, and 'what about Signal?'
TLDR: WhatsApp rebuilt its media handling in Rust to better block booby‑trapped images and videos for billions of users. Commenters applaud the security move, question the “largest rollout” brag, compare notes with Signal, and press for answers on app size and keeping quirky old files working
WhatsApp just dropped a flex: a new Rust-built safety layer guards your photo and video downloads, aiming to stop sneaky malware files before they bite. They even claim this might be the biggest Rust rollout ever, and the crowd? Half confetti, half cross‑examiner. Fans cheered that a memory‑safe language is finally protecting billions, with one user admitting they didn’t know so many bugs come from memory goofs. Cue the crab emojis.
But the comments didn’t let Meta stroll off. One camp asked: Is Signal doing this too? Another poked the “largest rollout” boast, noting WhatsApp’s sheer phone count probably wins the numbers game. A pragmatic dev dropped a reality check: rewriting media code isn’t just coding, it’s preserving the old, weird quirks so people’s “slightly broken” files still play — and they loved hearing WhatsApp used heavy testing to match behavior. The spiciest nitpick? File size. WhatsApp mentioned a bigger app due to Rust’s standard library but didn’t say how they tamed it, triggering a chorus of “So… did you just live with it?”
Between Stagefright flashbacks (that 2015 Android bug) and fresh Rust swagger, the vibe is: good move, now answer our nerdy questions — and yes, please keep our memes (and phones) safe
Key Points
- •WhatsApp deployed a Rust-based security layer to harden media handling against malware.
- •The 2015 Android Stagefright vulnerability prompted WhatsApp to add file-standard checks via its media library.
- •WhatsApp rewrote its “wamedia” library from C++ to Rust, developed in parallel and validated with differential fuzzing.
- •The Rust version replaced 160,000 lines of C++ with 90,000 lines of Rust (including tests) and improved performance and memory usage.
- •WhatsApp believes this is the largest global rollout of any Rust-written library, reaching billions of devices and browsers.