CVE-2026-43767: Apple macOS Buffer Overflow Vulnerability

CVE-2026-43767 Overview

CVE-2026-43767 is a memory handling vulnerability in Apple macOS that allows a local application to trigger unexpected system termination. Apple addressed the issue with improved memory handling in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6. The flaw is categorized under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer). Exploitation requires local access, low privileges, and user interaction, and impacts system availability without compromising confidentiality or integrity.

Critical Impact
A malicious or crafted application running on an affected macOS system can cause the operating system to terminate unexpectedly, resulting in denial of service for the host.

Affected Products

Apple macOS Sequoia versions prior to 15.7.8
Apple macOS Sonoma versions prior to 14.8.8
Apple macOS Tahoe versions prior to 26.6

Discovery Timeline

2026-07-27 - CVE-2026-43767 published to NVD
2026-07-30 - Last updated in NVD database

Technical Details for CVE-2026-43767

Vulnerability Analysis

CVE-2026-43767 stems from improper memory handling within a macOS system component. An application running locally on the host can trigger the flawed code path and force the operating system into an unexpected termination state. Apple's advisory language indicates the fix centers on improved memory handling, consistent with a memory safety issue such as an out-of-bounds access or corruption within a boundary buffer operation ([CWE-119]).

Exploitation requires a local attack vector, low privileges, and user interaction. The vulnerability does not expose data or allow modification of files, but it disrupts availability by crashing the system. There is no public evidence of exploitation, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Root Cause

The root cause is improper restriction of operations within the bounds of a memory buffer in a macOS system component. A malformed input or unexpected state processed by the vulnerable code triggers memory corruption or invalid access, which the kernel handles by terminating the affected process chain and, in turn, the system.

Attack Vector

An attacker must have local access to the macOS host and the ability to run an application. The application invokes the vulnerable interface with crafted inputs, which corrupts memory and causes the system to panic or terminate unexpectedly. Because user interaction is required, common delivery paths include social engineering to run a downloaded application or opening a malicious file that a helper process handles.

No verified proof-of-concept code is publicly available. Refer to Apple's advisories for component-specific details: Apple Support Article 128067, Apple Support Article 128071, and Apple Support Article 128072.

Detection Methods for CVE-2026-43767

Indicators of Compromise

Unexpected kernel panics or system restarts on macOS hosts running vulnerable versions.
Presence of .panic or .ips reports in /Library/Logs/DiagnosticReports/ correlated with a recently launched user application.
Repeated crashes tied to the same untrusted binary or installer package.

Detection Strategies

Monitor macOS crash and diagnostic reports for patterns that map a specific process to system termination events.
Correlate application execution telemetry with subsequent host reboots or agent disconnect events.
Track macOS version inventory and flag endpoints running versions earlier than 15.7.8, 14.8.8, or 26.6.

Monitoring Recommendations

Ingest macOS unified log and diagnostic report data into a centralized SIEM for panic-event correlation.
Alert on unsigned or newly introduced binaries that execute immediately before a crash event.
Track patch compliance for macOS endpoints and prioritize systems missing the July 2026 security updates.

How to Mitigate CVE-2026-43767

Immediate Actions Required

Apply Apple's July 2026 security updates: upgrade to macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, or macOS Tahoe 26.6.
Inventory macOS endpoints and identify hosts running affected versions.
Restrict installation and execution of untrusted applications through Gatekeeper and mobile device management (MDM) policies.

Patch Information

Apple released fixes in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6. Full advisory details are available at Apple Support Article 128067, Apple Support Article 128071, and Apple Support Article 128072.

Workarounds

Limit local user privileges and enforce least-privilege application execution until patches are deployed.
Enforce Gatekeeper, notarization, and System Integrity Protection (SIP) to reduce the risk of executing malicious applications.
Use MDM configuration profiles to block installation of unapproved software on managed endpoints.

bash

# Verify macOS version and confirm patch level
sw_vers -productVersion

# Trigger a software update check via CLI
sudo softwareupdate --list
sudo softwareupdate --install --all --restart