Apple products: memory corruption flaw under attack

What is affected

Apple products are found on ordinary personal computers and phones, so this is not only a problem for companies. If you use them and have not updated since the fix was released, you are exposed.

Apple iOS, iPadOS, macOS, and other Apple products contain an out-of-bounds write vulnerability in WebKit that may allow maliciously crafted web content to break out of Web Content sandbox. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.

What an attacker can do

This is a memory corruption flaw. It lets an attacker corrupt the program's memory by feeding it specially crafted content: a web page, a file or a network message. The result ranges from a crash to the attacker running their own code.

How it is reached

Over the internet or network

Access the attacker needs

No account needed

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. Update Apple products now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
2. Turn on automatic updates so the next fix arrives without you having to look for it.
3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• support.apple.comsupport.apple.com/en-us/122281
• support.apple.comsupport.apple.com/en-us/122283
• support.apple.comsupport.apple.com/en-us/122284
• support.apple.comsupport.apple.com/en-us/122285

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on March 13, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by April 3, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 3.8% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 90% of all scored vulnerabilities.

Its CVSS severity score is 10.0 out of 10 (critical), as recorded in the US National Vulnerability Database.

Technical description

An out-of-bounds write issue was addressed with improved checks to prevent unauthorized actions. This issue is fixed in Safari 18.3.1, iOS 15.8.4 and iPadOS 15.8.4, iOS 16.7.11 and iPadOS 16.7.11, iOS 18.3.2 and iPadOS 18.3.2, iPadOS 17.7.6, macOS Sequoia 15.3.2, visionOS 2.3.2, watchOS 11.4. Maliciously crafted web content may be able to break out of Web Content sandbox. This is a supplementary fix for an attack that was blocked in iOS 17.2. (Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals on versions of iOS before iOS 17.2.).