CVE-2026-84567: Apple macOS Buffer Overflow Vulnerability

CVE-2026-84567 Overview

CVE-2026-84567 is a memory handling vulnerability in Apple macOS that allows a local application to cause unexpected system termination. The flaw is classified under [CWE-119] (Improper Restriction of Operations within the Bounds of a Memory Buffer). Apple addressed the issue with improved memory handling in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7.

The vulnerability requires local access and low privileges. Exploitation results in a denial-of-service condition through system termination, with no impact on confidentiality or integrity.

Critical Impact
A local application can trigger unexpected system termination on unpatched macOS systems, disrupting availability of the host and any workloads running on it.

Affected Products

Apple macOS versions prior to Golden Gate 27
Apple macOS versions prior to Sequoia 15.8
Apple macOS versions prior to Tahoe 26.7

Discovery Timeline

2026-09-14 - CVE-2026-84567 published to NVD
2026-09-18 - Last updated in NVD database

Technical Details for CVE-2026-84567

Vulnerability Analysis

CVE-2026-84567 stems from improper memory handling within a macOS component. The flaw falls under [CWE-119], meaning operations on a memory buffer occur outside the intended boundary. When a local application triggers the vulnerable code path, the resulting memory corruption causes an unexpected system termination (kernel panic or equivalent halt).

Apple's advisory describes the fix succinctly: the issue was addressed with improved memory handling. This phrasing typically indicates additional bounds checking, validation of buffer sizes, or corrections to how memory is allocated and released in the affected subsystem. The vulnerability produces high availability impact but does not disclose data or permit code execution based on the published metrics.

The attack requires local access, meaning the adversary must already run code on the target machine. No user interaction is needed, and the scope remains unchanged, so exploitation stays confined to the vulnerable component.

Root Cause

The root cause is improper restriction of operations within a memory buffer in a macOS system component. Insufficient validation permits an application to reach a code path that mishandles memory and destabilizes the kernel or a privileged system process, forcing a shutdown or restart.

Attack Vector

An attacker with local, low-privileged access executes a crafted application that invokes the vulnerable interface. The malformed input drives the memory handling defect and triggers the termination. Because the vector is local and no user interaction is required, the flaw is most relevant on multi-user systems, shared workstations, and endpoints running untrusted code. Apple has not disclosed the specific component, and no public proof-of-concept is available.

Refer to the Apple Support Article 149035, Apple Support Article 149042, and Apple Support Article 149043 for vendor-published details.

Detection Methods for CVE-2026-84567

Indicators of Compromise

Unexpected kernel panics or system reboots correlated with the execution of a specific application or process.
Panic logs under /Library/Logs/DiagnosticReports/ referencing memory corruption or invalid access in a system component.
Repeated crash events tied to the same user session or non-Apple-signed binary.

Detection Strategies

Collect and centralize macOS .panic and .ips diagnostic reports for correlation across the fleet.
Alert on clusters of unexpected shutdowns occurring shortly after a new or unsigned process launches.
Track macOS build versions against Golden Gate 27, Sequoia 15.8, and Tahoe 26.7 to identify vulnerable endpoints.

Monitoring Recommendations

Forward system.log, wifi.log, and DiagnosticReports to a central log platform for retrospective analysis.
Monitor process execution telemetry for untrusted binaries that precede system termination events.
Establish a baseline for expected reboot frequency and alert on statistically significant deviations.

How to Mitigate CVE-2026-84567

Immediate Actions Required

Update all Apple macOS endpoints to macOS Golden Gate 27, macOS Sequoia 15.8, or macOS Tahoe 26.7 as appropriate for the installed major version.
Inventory macOS hosts and prioritize patching for shared systems, developer workstations, and any host that runs third-party applications.
Restrict installation and execution of untrusted applications on macOS endpoints until patches are deployed.

Patch Information

Apple released fixes in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. Patch details are published in Apple Support Article 149035, Apple Support Article 149042, and Apple Support Article 149043. Administrators should deploy the update through Software Update or their mobile device management (MDM) tooling.

Workarounds

No vendor-supplied workaround exists. Apply the security update as the primary remediation.
Enforce application allow-listing through Gatekeeper and MDM policies to reduce exposure to untrusted local code.
Limit standard user accounts from installing arbitrary software on endpoints that cannot be patched immediately.

bash

# Verify installed macOS version and trigger available updates
sw_vers -productVersion
sudo softwareupdate --list
sudo softwareupdate --install --all --restart