benhawkes

Well, we don't know for sure that an exploit exists for this bug on Android yet (the original exploit was for iOS via iMessage), but there's a reasonably high chance that one has been developed already. These types of exploits are in very high demand for Android right now, I've heard some eye-watering prices being mentioned recently.

Updating Chrome on an unsupported device would fix the issue, but you would still need an Android OS upgrade to fix the issue for apps like Signal and WhatsApp. Chrome bundles its own version of libwebp, but messaging apps and other highly exposed stuff like Gmail all use the OS provided interfaces for displaying images. Hopefully we'll start getting updates for security-supported Android devices in early October.

Chrome on MacOS was affected as well, yeah. Note that we don't know if attackers exploited the bug on platforms other than iOS, but its certainly possible that they did (I'd argue even probable).

Good questions -- yes other Chromium-based browsers would likely be affected by this bug. Many of these do a commendable job of following security updates in Chromium (like Brave), but others tend to fall quite far behind (like Samsung's SBrowser).

Chrome desktop was affected as well, both on Linux and Windows. Chrome bundles its own version of libwebp, so even if your Linux distribution hasn't patched yet, as long as Chrome is up-to-date you should be OK (in terms of browser attacks at least).

There's lots of wonderfully obscure image file formats that are supported by the major browsers and operating systems. For example you can load a KTX2 file (Khronos Texture Container) on MacOS, or a DNG file (Adobe Digital Negative) on Android. Lots of interesting and highly exposed attack surface for attackers to explore.