Apple OS OOB write DoS (CVE-2026-43666) fixed in iOS 18.7.9 et al
CVE-2026-43666 Published on May 11, 2026

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 18.7.9 and iPadOS 18.7.9, iOS 26.5 and iPadOS 26.5, macOS Sequoia 15.7.7, macOS Sonoma 14.8.7, macOS Tahoe 26.5, tvOS 26.5, visionOS 26.5, watchOS 26.5. An attacker on the local network may be able to cause a denial-of-service.

NVD

Vulnerability Analysis

CVE-2026-43666 is exploitable with local system access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:

LOCAL

Attack Complexity:

LOW

Privileges Required:

NONE

User Interaction:

NONE

Scope:

UNCHANGED

Confidentiality Impact:

NONE

Integrity Impact:

NONE

Availability Impact:

HIGH

Weakness Type

What is a Memory Corruption Vulnerability?

The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.

CVE-2026-43666 has been classified to as a Memory Corruption vulnerability or weakness.