CVE-2026-64790: Apple macOS Privilege Escalation Vulnerability

CVE-2026-64790 Overview

CVE-2026-64790 is a path handling vulnerability in Apple macOS that allows a local application to gain elevated privileges. The flaw stems from insufficient validation of file system paths, categorized as a path traversal weakness [CWE-22]. Apple addressed the issue with improved validation in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. Exploitation requires local access and user interaction, but successful attacks fully compromise confidentiality, integrity, and availability of the affected system. The vulnerability was published to the National Vulnerability Database (NVD) on 2026-09-14.

Critical Impact
A malicious application running on macOS can escape its intended privilege boundary and execute code with elevated system privileges, enabling full host compromise.

Affected Products

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

Discovery Timeline

2026-09-14 - CVE-2026-64790 published to NVD
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-64790

Vulnerability Analysis

CVE-2026-64790 is a local privilege escalation vulnerability rooted in improper path handling within macOS system components. Apple's advisory describes the fix as "improved validation," indicating the original code path accepted or resolved file paths without adequately verifying their canonical form or containment within expected directories. This class of weakness, tracked under [CWE-22] (Improper Limitation of a Pathname to a Restricted Directory), commonly enables an attacker-controlled process to reach files or resources outside its intended sandbox.

When a privileged macOS service operates on a path supplied or influenced by a lower-privileged application, an attacker can craft input that resolves to a sensitive location. The privileged process then reads, writes, or executes against that location on behalf of the attacker. The result is code execution or file manipulation at a higher privilege level than the calling application should possess.

Root Cause

The root cause is missing or incomplete validation of pathname components before they are consumed by a privileged operation. Path traversal sequences, symbolic links, or unexpected path prefixes were not fully normalized and checked against an allow-list of permitted locations. Apple's remediation adds stricter validation to reject or resolve such inputs before use.

Attack Vector

Exploitation requires local access with user interaction, matching the CVSS local attack vector. An attacker delivers or installs a malicious application that invokes the vulnerable code path with a crafted file path. The user must run the application, after which the attacker's code gains elevated privileges without further consent. No verified public proof-of-concept or in-the-wild exploitation has been reported.

No verified public exploit code is available. See the Apple Support Document 149035, Apple Support Document 149042, and Apple Support Document 149043 for vendor technical details.

Detection Methods for CVE-2026-64790

Indicators of Compromise

Unexpected files or executables written to system-owned directories such as /Library/, /System/, or /usr/local/ by non-administrative processes.
Newly installed launch daemons or launch agents under /Library/LaunchDaemons/ or /Library/LaunchAgents/ originating from unsigned or recently installed applications.
Processes spawned with elevated effective UIDs following execution of a recently installed third-party application.

Detection Strategies

Monitor endpoint telemetry for execve or posix_spawn events where a child process runs with higher privileges than its parent shortly after user application launch.
Correlate file system events showing path traversal patterns (for example, .. sequences or symbolic link resolution) targeting privileged directories.
Track macOS version inventory to identify hosts running builds prior to 15.8, 26.7, or Golden Gate 27.

Monitoring Recommendations

Enable Endpoint Security Framework (ESF) telemetry for process creation, file open, and code signing events.
Baseline legitimate installer and updater behavior to surface anomalous privileged file writes.
Alert on modifications to SUID/SGID binaries and system configuration files outside of approved update windows.

How to Mitigate CVE-2026-64790

Immediate Actions Required

Upgrade macOS Sequoia hosts to version 15.8 or later.
Upgrade macOS Tahoe hosts to version 26.7 or later.
Upgrade macOS Golden Gate hosts to version 27 or later.
Restrict installation of untrusted third-party applications through managed application allow-listing.

Patch Information

Apple released fixes in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. Refer to Apple Support Document 149035, Apple Support Document 149042, and Apple Support Document 149043 for build numbers and complete release notes.

Workarounds

No vendor-supplied workarounds exist; apply the security update as the primary remediation.
Enforce Gatekeeper and notarization requirements to block execution of unsigned applications.
Limit standard user accounts from installing software and require administrative approval for new applications.

bash

# Verify current macOS build and apply available updates
sw_vers -productVersion
softwareupdate --list
sudo softwareupdate --install --all --restart