CyberSecBulletin
CVE-2022-42842NVD status: Modified

macOS: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-42842 is a critical-severity out-of-bounds write vulnerability in macOS from Apple, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 11.7 as the first without the flaw, so updating macOS to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.44% chance of exploitation within 30 days, higher than 85% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update macOS to 11.7 or a later version.
  2. Update tvOS to 16.2 or 13.1 or 12.6, whichever matches your release line, or a later version.
  3. Update watchOS to 9.2 or a later version.
  4. Read the advisory on support.apple.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ApplemacOSbefore 11.711.7
AppletvOSbefore 16.2; before 13.1; before 12.616.2, 13.1, 12.6
ApplewatchOSbefore 9.29.2
AppleiPadOSbefore 16.216.2
AppleIphone OSbefore 16.216.2

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)

Official description

The issue was addressed with improved memory handling. This issue is fixed in tvOS 16.2, macOS Monterey 12.6.2, macOS Ventura 13.1, macOS Big Sur 11.7.2, iOS 16.2 and iPadOS 16.2, watchOS 9.2. A remote user may be able to cause kernel code execution.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in macOS

All macOS vulnerabilities

Recent Out-of-bounds Write vulnerabilities

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