CVE-2026-43789: Apple macOS Information Disclosure Flaw

CVE-2026-43789 Overview

CVE-2026-43789 is a missing authorization vulnerability [CWE-862] affecting Apple macOS. The flaw allows an application to bypass sandbox restrictions and access user-sensitive data without proper authorization. Apple addressed the issue by adding additional sandbox restrictions in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. The vulnerability impacts the confidentiality of user data on affected systems. No exploitation in the wild has been reported, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog.

Critical Impact
A malicious application installed on a vulnerable macOS system can read user-sensitive data that should be protected by sandbox enforcement.

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-2026-43789 published to NVD
2026-09-17 - Last updated in NVD database

Technical Details for CVE-2026-43789

Vulnerability Analysis

CVE-2026-43789 arises from insufficient sandbox restrictions in Apple macOS. The macOS sandbox enforces mandatory access controls that limit what resources an application can reach. In vulnerable versions, the sandbox profile fails to restrict access paths that lead to user-sensitive data. Apple's advisory states the fix introduces additional sandbox restrictions to close the exposure.

The issue is classified under CWE-862 (Missing Authorization). An application running with standard privileges can retrieve data that should require explicit user consent or entitlement checks. This category of flaw typically undermines Transparency, Consent, and Control (TCC) protections that macOS uses to guard sensitive resources such as Contacts, Calendars, Documents, and Photos.

Root Cause

The root cause is a gap in the sandbox policy enforcement layer. The affected components did not apply sufficient authorization checks before granting access to protected user data. Apple's remediation strengthens the sandbox profile rather than modifying application-level code, indicating the missing control lived in the platform's access-mediation layer.

Attack Vector

Exploitation requires an attacker-controlled application to run on the target macOS system. The application does not need elevated privileges or user interaction beyond initial execution. Once running, the app can invoke the affected code paths to read user-sensitive data outside its intended sandbox scope. Delivery vectors include trojanized installers, malicious App Store submissions, or supply chain compromise of legitimate software.

Apple has not published proof-of-concept exploitation code. Public technical details are limited to the vendor advisories linked below. Refer to Apple Support Document #149035, Apple Support Document #149042, and Apple Support Document #149043 for vendor guidance.

Detection Methods for CVE-2026-43789

Indicators of Compromise

Unsigned or ad-hoc signed applications reading files under ~/Library/Application Support/, ~/Documents/, or other TCC-protected locations without corresponding user consent prompts.
Processes issuing unexpected file system reads outside their declared sandbox container paths.
Anomalous sandboxd denial patterns followed by successful access attempts on the same resources.

Detection Strategies

Monitor Endpoint Security framework events (ES_EVENT_TYPE_NOTIFY_OPEN, ES_EVENT_TYPE_NOTIFY_READDIR) for applications accessing user-sensitive directories they have no entitlement to reach.
Correlate TCC database access events with application code signing identity to identify apps operating outside their sandbox scope.
Baseline expected file access per application and alert on deviations targeting personal data stores.

Monitoring Recommendations

Enable unified logging with the com.apple.sandbox and com.apple.TCC subsystems and forward records to a central analytics platform.
Track macOS version inventory across managed endpoints to identify systems below Sequoia 15.8, Tahoe 26.7, or Golden Gate 27.
Review application installation events and flag unsigned binaries or apps installed outside the Mac App Store.

How to Mitigate CVE-2026-43789

Immediate Actions Required

Upgrade all Apple macOS endpoints to macOS Golden Gate 27, macOS Sequoia 15.8, or macOS Tahoe 26.7 as appropriate for each device.
Audit installed third-party applications and remove software from untrusted publishers.
Restrict application installation to signed, notarized binaries using Gatekeeper enforcement policies.

Patch Information

Apple released fixes in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. Detailed release notes are available in Apple Support Document #149035, Apple Support Document #149042, and Apple Support Document #149043. Deploy the appropriate update through Software Update or your mobile device management (MDM) platform.

Workarounds

Limit installation of untrusted applications until patches are deployed across the fleet.
Enforce strict Gatekeeper settings to allow only App Store or identified developer software.
Use MDM configuration profiles to restrict access to sensitive directories and disable execution of unsigned binaries.

bash

# Verify macOS build and confirm the system is on a patched release
sw_vers -productVersion
sw_vers -buildVersion

# Enforce Gatekeeper to allow only App Store and identified developers
sudo spctl --master-enable
spctl --status