CyberSecBulletin
CVE-2026-43807NVD status: Modified

iOS and iPadOS: Buffer Copy without Checking Size of Input

Published Updated By the CyberSecBulletin desk

CVE-2026-43807 is a critical-severity buffer copy without checking size of input vulnerability in iOS and iPadOS 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 versions 18.7.10, 26.5.2 as the first without the flaw, so updating iOS and iPadOS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.74% chance of exploitation within 30 days, higher than 55% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update iOS and iPadOS to 18.7.10 or 26.5.2, whichever matches your release line, or a later version.
  2. Update macOS to 14.8.8 or 15.7.8 or 26.5.2, whichever matches your release line, or a later version.
  3. Update tvOS to 26.6 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
AppleiOS and iPadOSbefore 18.7.10; before 26.5.218.7.10, 26.5.2
ApplemacOSbefore 14.8.8; before 15.7.8; before 26.5.214.8.8, 15.7.8, 26.5.2
AppletvOSbefore 26.626.6
ApplevisionOSbefore 26.626.6
ApplewatchOSbefore 26.626.6
AppleiPadOSbefore 26.5.226.5.2
AppleIphone OSbefore 26.5.226.5.2

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 CISA (ADP).

Official description

A buffer overflow was addressed with improved bounds checking. This issue is fixed in iOS 18.7.10 and iPadOS 18.7.10, iOS 26.5.2 and iPadOS 26.5.2, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.5.2, tvOS 26.6, visionOS 26.6, watchOS 26.6. A malicious accessory may be able to cause unexpected app termination.

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

The underlying weakness: Buffer Copy without Checking Size of Input

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output 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 Buffer Copy without Checking Size of Input vulnerabilities (CWE-120)

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

Other vulnerabilities in iOS and iPadOS

All iOS and iPadOS vulnerabilities

Recent Buffer Copy without Checking Size of Input vulnerabilities

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