Actively exploited vulnerability

Apple iOS, iPadOS, and macOS: memory corruption flaw under attack

CVE-2021-30869 · Apple iOS, iPadOS, and macOS Type Confusion Vulnerability

Concerns everyone who uses it7.8 high

What is affected

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

Apple iOS, iPadOS, and macOS contain a type confusion vulnerability in the XNU which may allow a malicious application to execute code with kernel privileges.

CISA's description

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
Needs access to the device or a file opened on it
Access the attacker needs
No account needed
Does the victim have to do something?
Yes, the victim must open or click something

What to do

  1. Update Apple iOS, iPadOS, and macOS 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 updates per vendor instructions.

Action required by CISA for US federal agencies

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on November 3, 2021, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by November 17, 2021, 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 4.1% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 91% of all scored vulnerabilities.

Its CVSS severity score is 7.8 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

A type confusion issue was addressed with improved state handling. This issue is fixed in iOS 12.5.5, iOS 14.4 and iPadOS 14.4, macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, Security Update 2021-006 Catalina. A malicious application may be able to execute arbitrary code with kernel privileges. Apple is aware of reports that an exploit for this issue exists in the wild.

NIST National Vulnerability Database
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