CVE-2026-84580: Apple macOS Privilege Escalation Vulnerability

CVE-2026-84580 Overview

CVE-2026-84580 is a sandbox escape vulnerability affecting Apple macOS. A malicious application can break out of its sandbox and access resources outside its designated boundary. Apple addressed the issue with improved checks in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7.

The vulnerability is categorized under [CWE-862] Missing Authorization. It requires local access with low privileges but no user interaction, and results in a scope change with high impact to confidentiality and integrity.

Critical Impact
An application running inside the macOS sandbox can escape the sandbox boundary, gaining access to files, resources, and system components that should be inaccessible to sandboxed processes.

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-2026-84580 published to the National Vulnerability Database
2026-09-17 - Last updated in NVD database

Technical Details for CVE-2026-84580

Vulnerability Analysis

The vulnerability allows a sandboxed application to escape the macOS App Sandbox. The App Sandbox is a macOS access control technology that restricts an application's access to system resources and user data. Escaping it removes those restrictions and exposes protected APIs, files, and interprocess communication (IPC) channels.

Apple's advisory describes the fix as addressing the issue with improved checks. This wording indicates that the vulnerable code path performed insufficient validation before granting or trusting an operation. Attackers can leverage the flaw to perform actions outside their entitlements and elevate privilege on the system.

Root Cause

The root cause is a missing authorization check ([CWE-862]) in a macOS component reachable from sandboxed code. The vulnerable code accepted a request or state transition without verifying that the caller was permitted to perform the operation. Apple's remediation adds the missing validation logic.

Attack Vector

Exploitation requires local access. An attacker must first deliver and execute code inside a sandboxed process, for example a malicious application installed on the device or a compromised legitimate app. Once running, the code invokes the vulnerable interface to bypass sandbox restrictions and reach resources under a broader security scope. No user interaction is required to trigger the escape.

No public proof-of-concept exploit or CISA KEV listing exists for CVE-2026-84580 at the time of publication.

Refer to Apple's advisories for component-level detail: Apple Support Article #149035, Apple Support Article #149042, and Apple Support Article #149043.

Detection Methods for CVE-2026-84580

Indicators of Compromise

Sandboxed applications spawning child processes outside their bundle or entitlements
Sandboxed processes accessing files in ~/Library, /Library, or other protected paths not declared in their entitlements
Unexpected XPC or Mach IPC connections initiated from sandboxed apps to privileged system services
New or modified LaunchAgents and LaunchDaemons created by processes that should not have write access to those locations

Detection Strategies

Correlate process ancestry with code signing and sandbox entitlements to identify processes acting outside their declared scope
Monitor sandboxd and kernel log entries for sandbox violations and denied operations that precede unusual activity
Baseline normal file, network, and IPC behavior for common sandboxed applications and alert on deviations
Track application installations from outside the Mac App Store and elevate scrutiny of their runtime behavior

Monitoring Recommendations

Ingest macOS Endpoint Security Framework (ESF) telemetry covering process execution, file access, and IPC events into a central analytics pipeline
Retain Unified Log entries from com.apple.sandbox and related subsystems for forensic review
Alert on privilege changes, entitlement mismatches, and modifications to TCC.db originating from non-system processes
Review macOS version inventory to identify hosts still running builds prior to Golden Gate 27, Sequoia 15.8, or Tahoe 26.7

How to Mitigate CVE-2026-84580

Immediate Actions Required

Update all macOS endpoints to macOS Golden Gate 27, macOS Sequoia 15.8, or macOS Tahoe 26.7
Inventory managed Macs and prioritize patching of systems that install untrusted or third-party applications
Restrict installation of unsigned or non-notarized applications through Gatekeeper policy enforcement
Audit installed applications for suspicious bundles delivered outside approved distribution channels

Patch Information

Apple released fixes in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. Detailed component and version information is available in Apple Support Article #149035, Apple Support Article #149042, and Apple Support Article #149043.

Workarounds

Limit local user privileges and enforce standard (non-administrator) accounts where possible
Enforce application allow-listing through Mobile Device Management (MDM) to prevent execution of unapproved software
Disable installation of applications from unidentified developers using Gatekeeper and System Policy controls
Monitor and remove applications requesting entitlements that exceed their functional requirements

bash

# Verify macOS build meets or exceeds the patched versions
sw_vers -productVersion
sw_vers -buildVersion

# Enforce Gatekeeper to only allow signed, notarized applications
sudo spctl --master-enable
sudo spctl --global-enable