Both iOS 15.0.2 and iPadOS 15.0.2, which are available to download on supported devices now, include a fix for a memory corruption vulnerability that allowed an application to execute arbitrary code with the highest level of device access, Apple says on its security support page.
While details on the bug remain thin, Apple warns that it "may have been actively exploited" — so it's probably a good idea to update your devices right away.
The updates also address a number of other glitches in iOS 15 and iPadOS 15, including an issue that caused the iPhone Leather Wallet and with MagSafe not to connect to Find My, a bug that could cause AirTags not to appear in the Find My Items tab, and another that caused CarPlay to fail to open audio apps or to disconnect during playback. There's also a fix for a glitch that saw photos saved to your library from Messages deleted after removing the associated thread or message.
Apple is currently testing the first major update to iOS 15.1, which will be the first major update to iOS 15. This update will re-enable SharePlay in FaceTime, add new iPhone 13 Pro and Pro Max camera features and bring support for adding a COVID-19 vaccination card to Apple Wallet. It'll probably include a handful of bug fixes, too.