CVE-2026-43690: Apple macOS Race Condition Vulnerability

CVE-2026-43690 Overview

CVE-2026-43690 is a race condition vulnerability in Apple macOS that allows a local user to read kernel memory. Apple addressed the flaw with improved locking in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. The weakness is classified under [CWE-362] (Concurrent Execution using Shared Resource with Improper Synchronization).

Exploitation requires local access and elevated attack complexity, limiting opportunistic abuse. However, successful exploitation exposes kernel memory contents, which can leak sensitive data such as cryptographic keys, pointers useful for KASLR bypass, or credentials cached by kernel subsystems.

Critical Impact
A local attacker who wins the race window can read arbitrary kernel memory, enabling information disclosure that supports further privilege escalation or sandbox escape chains.

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-2026-43690 published to NVD
2026-09-17 - Last updated in NVD database

Technical Details for CVE-2026-43690

Vulnerability Analysis

The vulnerability is a race condition in a macOS kernel component where two or more concurrent execution paths access a shared resource without adequate synchronization. When a local process invokes the affected code path with precise timing, the kernel returns data from memory regions that should not be exposed to userland.

Apple's advisory states the fix consists of improved locking, indicating the original code either omitted a lock, released it too early, or used an insufficient synchronization primitive. The result is a time-of-check to time-of-use style window where kernel state can be observed mid-transition.

The confidentiality impact is high while integrity and availability remain unaffected. This aligns with an information disclosure primitive rather than a memory corruption bug. Leaked kernel pointers and object contents typically serve as a building block for chained exploits targeting privilege escalation.

Root Cause

The root cause is improper synchronization on a shared kernel resource, categorized as [CWE-362]. Concurrent threads can observe partially updated state or free memory contents that were not zeroed before release. Apple did not publish the specific subsystem, but the remediation pattern points to missing or incorrectly scoped lock acquisitions around a read path.

Attack Vector

Exploitation requires local code execution on the target macOS host with low privileges. The attacker triggers the vulnerable code path repeatedly while a second thread mutates the shared resource, attempting to hit the narrow race window. Success returns kernel memory bytes to the unprivileged process without any user interaction.

The high attack complexity reflects the timing precision needed to win the race consistently. No sandbox escape is required to reach the vulnerable interface, and no network access is involved. Refer to Apple Support Article #149035, Apple Support Article #149042, and Apple Support Article #149043 for vendor guidance.

Detection Methods for CVE-2026-43690

Indicators of Compromise

Unsigned or unnotarized binaries executing tight loops against kernel syscalls or IOKit interfaces from non-privileged user contexts.
Processes exhibiting sustained high CPU with repeated mach_msg or ioctl calls targeting the same kernel object.
Unexpected launch agents or daemons dropped into ~/Library/LaunchAgents/ or /Library/LaunchDaemons/ immediately before anomalous kernel activity.

Detection Strategies

Monitor for local processes performing high-frequency, low-latency syscalls consistent with race-condition brute forcing.
Alert on binaries executing outside standard application bundle paths that request kernel interfaces normally reserved for system components.
Correlate kernel panic reports and sysdiagnose bundles with process ancestry to identify preceding suspicious activity.

Monitoring Recommendations

Ingest macOS Endpoint Security Framework (ESF) telemetry into a central data lake and retain process, file, and syscall events.
Track macOS build versions across the fleet and flag hosts running versions older than 15.8, 26.7, or Golden Gate 27.
Baseline normal syscall rates per binary and alert on statistical outliers that may indicate race-condition exploitation attempts.

How to Mitigate CVE-2026-43690

Immediate Actions Required

Deploy Apple's security updates to upgrade affected endpoints to macOS Sequoia 15.8, macOS Tahoe 26.7, or macOS Golden Gate 27.
Inventory macOS assets and prioritize patching for multi-user systems and developer workstations where local access is broader.
Restrict installation and execution of untrusted third-party binaries via Gatekeeper and application allowlisting policies.

Patch Information

Apple released fixes in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. Detailed remediation notes are documented in Apple Support Article #149035, Apple Support Article #149042, and Apple Support Article #149043. Apply the update matching each endpoint's macOS train.

Workarounds

No vendor-supplied workaround exists; patching is the only supported remediation.
Limit local user accounts on shared macOS hosts and enforce least-privilege policies to reduce the attack surface until patches are applied.
Enable full System Integrity Protection (SIP) and disallow loading of unsigned kernel extensions to constrain adjacent exploitation paths.

bash

# Verify the installed macOS version against the patched builds
sw_vers -productVersion

# Trigger a software update check and install available patches
sudo softwareupdate --install --all --restart