Out-of-bounds write in macOS - CVE-2026-86876

Vulnerability identifier: #VU149744

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-86876

CWE-ID: CWE-787

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to bypass implemented security restrictions.

The vulnerability exists due to an out-of-bounds write in CoreMedia when processing media content. A local user can trigger the out-of-bounds write to bypass implemented security restrictions.

macOS
Apple iOS
iPadOS
watchOS
visionOS

Install update from vendor's website.

macOS - addressed in versions 26.7 25G229, 15.8 24H23, 27.0 26A428
Apple iOS - addressed in versions 26.7 23H24, 27.0 24A427, 27.0 24A437
iPadOS - addressed in versions 26.7 23H24, 27.0 24A437
watchOS - update to 27.0 24R364
visionOS - update to 27.0

• https://support.apple.com/en-us/149042

• Multiple vulnerabilities in macOS Tahoe
• Multiple vulnerabilities in macOS Sequoia
• Multiple vulnerabilities in macOS
• Multiple vulnerabilities in Apple iOS 26 and iPadOS 26
• Multiple vulnerabilities in Apple iOS 27 and iPadOS 27
• Multiple vulnerabilities in Apple visionOS
• Multiple vulnerabilities in Apple watchOS