CVE-2026-28888: Apple macOS Privilege Escalation Flaw

CVE-2026-28888 Overview

CVE-2026-28888 is a race condition vulnerability affecting Apple macOS that allows a malicious application to gain root privileges on the local system. Apple addressed the flaw with improved state handling across multiple supported macOS releases. The issue is classified under [CWE-362] (Concurrent Execution using Shared Resource with Improper Synchronization).

The vulnerability requires local access and high attack complexity to exploit. However, successful exploitation results in full root-level compromise of the affected host. Apple has shipped fixes in macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, and macOS Tahoe 26.4.

Critical Impact
A local application can win a race condition to elevate to root privileges, granting full control over the affected macOS system.

Affected Products

Apple macOS Sequoia versions prior to 15.7.5
Apple macOS Sonoma versions prior to 14.8.5
Apple macOS Tahoe versions prior to 26.4

Discovery Timeline

2026-03-25 - CVE-2026-28888 published to NVD
2026-03-25 - Last updated in NVD database

Technical Details for CVE-2026-28888

Vulnerability Analysis

The vulnerability stems from improper synchronization between concurrent operations in a privileged macOS component. When two or more execution threads access shared state without adequate locking, an attacker-controlled process can manipulate state between a check and a subsequent action. This is a classic Time-of-Check Time-of-Use (TOCTOU) class flaw tracked under [CWE-362].

Apple's advisory states the issue was addressed with improved state handling. This indicates the original code path failed to atomically validate and consume privileged state. An attacker exploiting the race window can cause the operating system to perform a privileged action on behalf of an unprivileged caller.

Successful exploitation grants root privileges, which break the macOS security boundary between user-mode applications and system services. From root, an attacker can disable security controls, persist on the host, and access sensitive user data.

Root Cause

The root cause is a missing or insufficient synchronization primitive guarding a privileged state transition. Two concurrent code paths can observe inconsistent views of the same resource. Apple's fix introduces stricter state handling to close the race window.

Attack Vector

Exploitation requires the attacker to execute code locally on the target macOS system, typically via a malicious application. The attack complexity is high because the attacker must reliably win a timing race against the kernel or a system service. No user interaction or prior authentication is required once the malicious application runs.

No public proof-of-concept code or in-the-wild exploitation has been reported. The CVE is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-28888

Indicators of Compromise

Unexpected child processes spawned by user applications running with uid=0 or euid=0
New or modified files under /Library/LaunchDaemons/, /System/Library/, or other root-owned paths created shortly after application launch
Unsigned or ad-hoc signed binaries invoking privileged system services in rapid, repeated succession indicative of race-window probing

Detection Strategies

Monitor endpoint telemetry for processes that transition from a standard user context to root without an expected sudo, authopen, or XPC authorization prompt
Alert on tight loops of fork(), execve(), or XPC calls targeting privileged helper services, which are characteristic of race condition exploitation attempts
Correlate process privilege elevations with the parent application's code signature and notarization status

Monitoring Recommendations

Enable Endpoint Security Framework (ESF) event collection for ES_EVENT_TYPE_NOTIFY_EXEC and ES_EVENT_TYPE_NOTIFY_SETUID events
Forward macOS unified logs to a centralized analytics platform and retain authorization, securityd, and XPC subsystem entries
Baseline normal privileged operations per host and flag deviations, particularly from non-administrative user accounts

How to Mitigate CVE-2026-28888

Immediate Actions Required

Update affected hosts to macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, or macOS Tahoe 26.4 as soon as testing permits
Inventory macOS endpoints and prioritize systems where untrusted users can install or execute third-party applications
Restrict installation of unsigned or non-notarized applications via Gatekeeper and MDM configuration profiles

Patch Information

Apple has released patches in macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, and macOS Tahoe 26.4. Refer to the vendor advisories for full details: Apple Support Document #126794, Apple Support Document #126795, and Apple Support Document #126796.

Workarounds

Enforce least-privilege application allowlisting via MDM to prevent execution of untrusted binaries on managed Macs
Require administrator-only installation of new applications and disable execution from user-writable paths where feasible
Apply the vendor patch as the only durable remediation, since no configuration change fully closes the race condition window

bash

# Verify the installed macOS version meets the patched baseline
sw_vers -productVersion

# Trigger a software update check on the endpoint
sudo softwareupdate --list
sudo softwareupdate --install --all --restart