CVE-2026-84550: Apple macOS Race Condition Vulnerability

CVE-2026-84550 Overview

CVE-2026-84550 is a race condition vulnerability [CWE-362] affecting multiple versions of Apple macOS. A local application can trigger the flaw to cause unexpected system termination, resulting in denial of service on the host. Apple addressed the issue by adding validation logic in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. The vulnerability requires local access and low-privilege execution but no user interaction. Public exploit code is not available, and CISA has not added the flaw to its Known Exploited Vulnerabilities catalog. The EPSS probability places exploitation likelihood in the low range for the near term.

Critical Impact
A local attacker with the ability to run code on a macOS host can crash the operating system, producing an availability impact until the system reboots.

Affected Products

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

Discovery Timeline

2026-09-14 - CVE-2026-84550 published to NVD
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-84550

Vulnerability Analysis

CVE-2026-84550 is a race condition in Apple macOS that a local application can exercise to cause unexpected system termination. Apple's advisory notes the fix consisted of additional validation, indicating a missing or insufficient check between concurrent operations on shared state.

Race conditions of this class [CWE-362] arise when two or more code paths operate on the same resource without adequate synchronization. An attacker who can time operations precisely may observe or manipulate the resource in an intermediate state. In macOS kernel or privileged system components, such states can produce invalid pointers, inconsistent object lifetimes, or corrupted metadata that force a panic.

The impact is limited to availability. Confidentiality and integrity are not affected, according to the published CVSS vector. Exploitation requires local access and low-privileged code execution on the target host.

Root Cause

The root cause is insufficient validation of shared state during concurrent operations. Apple's remediation description explicitly cites additional validation as the fix, which typically implies added bounds checks, state re-verification after locking, or defensive checks before the resource is consumed.

Attack Vector

An attacker must execute code locally on the target macOS system. The attacker triggers the vulnerable code path repeatedly, timing operations to win the race window. Successful exploitation causes a kernel or system-service panic, terminating the operating system and disrupting active workloads. No user interaction is required, and the attacker does not need elevated privileges beyond running a standard application.

No public proof-of-concept code is available. See the Apple Support Article #149035, Apple Support Article #149042, and Apple Support Article #149043 for vendor technical details.

Detection Methods for CVE-2026-84550

Indicators of Compromise

Unexpected kernel panics or system reboots on macOS hosts running versions prior to Golden Gate 27, Sequoia 15.8, or Tahoe 26.7.
Panic logs in /Library/Logs/DiagnosticReports/ referencing race-condition-related stack traces in kernel or system services.
Repeated crash signatures originating from the same non-privileged process across multiple hosts.

Detection Strategies

Collect and centralize macOS panic.ips and .diag diagnostic reports for correlation across the fleet.
Alert on abnormal frequency of unexpected shutdown events on endpoints, particularly those tied to a specific user process.
Correlate process execution telemetry with panic events to identify processes that consistently precede system termination.

Monitoring Recommendations

Ingest endpoint diagnostic and crash telemetry into a centralized analytics platform for cross-host pattern detection.
Track macOS build versions across managed devices to prioritize unpatched systems for investigation.
Baseline expected reboot frequency per device and alert on statistical outliers.

How to Mitigate CVE-2026-84550

Immediate Actions Required

Inventory macOS devices and identify hosts running versions earlier than Golden Gate 27, Sequoia 15.8, or Tahoe 26.7.
Deploy the Apple security updates through your mobile device management (MDM) platform as the primary remediation.
Restrict installation and execution of untrusted local applications until affected hosts are patched.

Patch Information

Apple released fixes in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. Refer to Apple Support Article #149035, Apple Support Article #149042, and Apple Support Article #149043 for the corresponding release notes and installation guidance. Apply updates through Software Update or your MDM rollout process.

Workarounds

No vendor-supplied workaround exists; upgrading to a fixed macOS release is the only complete remediation.
Apply application allowlisting to limit which local processes can execute on high-value hosts.
Enforce least privilege for standard user accounts to reduce the population of processes that can reach the vulnerable code path.

bash

# Verify installed macOS version and prioritize patching
sw_vers -productVersion
softwareupdate --list
sudo softwareupdate --install --all --restart