CVE-2026-28976: Apple macOS Privilege Escalation Flaw

CVE-2026-28976 Overview

CVE-2026-28976 is an information disclosure vulnerability affecting Apple macOS. Apple addressed the issue with additional validation logic in macOS Tahoe 26.5. According to the advisory, the flaw could allow an app to gain root privileges. The weakness is categorized under [CWE-200] (Exposure of Sensitive Information to an Unauthorized Actor).

The vulnerability is network-attackable with low complexity and no privileges or user interaction required. No public proof-of-concept exists, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog.

Critical Impact

An application may leak sensitive information that enables escalation to root privileges on affected macOS systems.

Affected Products

• Apple macOS (versions prior to macOS Tahoe 26.5)
• Systems where applications run with standard user privileges
• macOS endpoints in enterprise and consumer deployments

Discovery Timeline

• 2026-05-11 - CVE-2026-28976 published to NVD
• 2026-05-13 - Last updated in NVD database

Technical Details for CVE-2026-28976

Vulnerability Analysis

The vulnerability is an information leakage flaw in Apple macOS. Apple's advisory states the issue was addressed with additional validation. An application running on the system can leverage the leaked information to gain root privileges. This represents a confidentiality-impacting weakness that ultimately enables local privilege escalation.

The issue maps to [CWE-200], which covers exposure of sensitive information to actors not explicitly authorized to access it. In this case, the leaked data appears to provide material useful for elevating an unprivileged process to root.

Root Cause

Apple has not published technical specifics about the underlying component. The vendor advisory indicates that insufficient validation in a privileged macOS subsystem permitted disclosure of sensitive data. The fix introduces additional validation checks to prevent unauthorized access to that data.

Attack Vector

An attacker requires the ability to run code on the target macOS host, typically through a malicious or compromised application. Once executed, the app queries the affected component to harvest the leaked information. The attacker then uses this information to escalate to root, bypassing standard macOS privilege boundaries.

No verified exploitation code is publicly available. Refer to the Apple Security Advisory for vendor-supplied details.

Detection Methods for CVE-2026-28976

Indicators of Compromise

• Unexpected processes running with root or elevated entitlements that were launched from user-writable paths
• Applications making unusual calls to privileged macOS subsystems or IPC endpoints
• New launch daemons or launch agents written to /Library/LaunchDaemons/ or /Library/LaunchAgents/ shortly after an untrusted app executed

Detection Strategies

• Monitor process lineage for non-system binaries spawning child processes that transition to UID 0
• Inspect endpoints for macOS builds older than Tahoe 26.5 to identify exposed hosts
• Correlate application installs from outside the App Store with subsequent privilege transitions

Monitoring Recommendations

• Enable macOS Endpoint Security Framework (ESF) telemetry for ES_EVENT_TYPE_NOTIFY_EXEC and ES_EVENT_TYPE_NOTIFY_SETUID events
• Track Gatekeeper and XProtect events for newly executed unsigned or ad-hoc signed applications
• Audit Unified Logs for authorization service anomalies and unexpected sudo or authd activity

How to Mitigate CVE-2026-28976

Immediate Actions Required

• Update affected systems to macOS Tahoe 26.5 or later as published in the Apple Security Advisory
• Inventory macOS endpoints to confirm patch coverage across managed and unmanaged devices
• Restrict installation of unsigned or untrusted applications via MDM policy

Patch Information

Apple resolved CVE-2026-28976 in macOS Tahoe 26.5 by adding validation to the affected component. Administrators should deploy the update through Software Update, MDM, or Apple Business Manager. Confirm the build version after deployment to verify remediation.

Workarounds

• No vendor-supplied workaround exists; apply the macOS Tahoe 26.5 update
• Limit local code execution by enforcing application allowlisting through Gatekeeper and Notarization policies
• Reduce attack surface by removing unnecessary third-party applications from sensitive hosts

# Verify macOS build and trigger update
sw_vers -productVersion
sudo softwareupdate --install --all --restart