Apple urges all iOS users to update their systems immediately to avoid falling victim to a use-after-free vulnerability that could allow an attacker to execute arbitrary code on the victim’s device.

Use-after-free (UAF) attacks exploit a vulnerability in how applications manage dynamic memory allocation. Dynamic memory stores blocks of any size are quickly used and then released and are managed by headers that help apps understand which blocks are occupied.

In some cases, memory headers are not cleared properly. This is where a potential attacker can insert malicious code that is then picked up by another app and executed at the original buffer address.

In order to exploit this vulnerability, an attacker would need the victim to access a malicious web page that would compromise the device and allow the execution of arbitrary code.

All web browsers available on iOS, from Safari to Chrome to Firefox and beyond, use WebKit, making any iOS device potentially vulnerable. In addition, a number of macOS and Linux browsers use WebKit. Desktop browsers therefore also need to be updated.

According to Apple, the iPhone 6S and later, all iPad Pro models, iPad Air 2 and above, iPad 5th Gen and above, iPad Mini 4 and above, and iPod Touch seventh-generation devices can download Update 15.3. 1 for iOS and iPadOS.