CVE-2025-43340: Apple macOS Privilege Escalation Flaw

CVE-2025-43340 Overview

CVE-2025-43340 is a permissions vulnerability in Apple macOS that allows an application to break out of its sandbox. Apple addressed the issue with additional restrictions in macOS Tahoe 26. The flaw is categorized under [CWE-284] (Improper Access Control) and requires local access combined with user interaction to exploit. A sandbox escape grants a malicious app access to resources outside its intended security boundary, expanding the blast radius of any initial compromise on the host.

Critical Impact
A malicious or compromised application can escape the macOS sandbox and gain access to files, system resources, and capabilities beyond its declared entitlements.

Affected Products

Apple macOS versions prior to macOS Tahoe 26
Applications relying on the macOS App Sandbox for isolation
Third-party apps distributed through the Mac App Store and notarized channels

Discovery Timeline

2025-09-15 - CVE-2025-43340 published to the National Vulnerability Database (NVD)
2025-09-15 - Apple releases macOS Tahoe 26 with the fix, documented in the Apple Support Document
2025-09 - Technical details disclosed via the Full Disclosure Post
2025-11-03 - Last updated in the NVD database

Technical Details for CVE-2025-43340

Vulnerability Analysis

The vulnerability stems from a permissions issue within macOS that allowed a sandboxed application to perform actions outside its assigned security perimeter. The macOS App Sandbox enforces fine-grained access controls based on entitlements declared by each application. When permissions checks are incomplete or inconsistent, an application can reach resources the sandbox is designed to block.

Apple's advisory states the fix introduces additional restrictions, indicating that the prior policy did not sufficiently constrain access to a specific resource or operation. The issue requires local execution context, meaning an attacker must already run code on the system, typically through a malicious or compromised app. User interaction is also required, which aligns with delivery vectors such as opening a file or launching an untrusted application.

A successful sandbox escape impacts confidentiality, integrity, and availability. The attacker can read user data, modify files, and interfere with system or application behavior outside the sandboxed process.

Root Cause

The root cause is improper access control within the sandbox enforcement logic. A code path failed to apply the restrictions required to keep a sandboxed process contained. Apple's patch closes the gap by tightening these permission checks rather than altering the sandbox architecture.

Attack Vector

An attacker delivers a malicious application, plugin, or document that triggers execution within a sandboxed process. After the user launches or interacts with the app, the process invokes the affected code path and reaches resources outside the sandbox. From there, the attacker can stage further actions such as credential theft, persistence, or privilege escalation. Public exploitation details are described in the Full Disclosure Post. No proof-of-concept code is bundled with this advisory.

Detection Methods for CVE-2025-43340

Indicators of Compromise

Sandboxed applications accessing file paths outside their container, such as locations under ~/Library belonging to other apps or /private/var system directories.
Unsigned or ad-hoc signed binaries spawning child processes that perform privileged file operations.
Unexpected XPC service calls originating from apps with restrictive entitlements.

Detection Strategies

Monitor sandboxd and Endpoint Security framework events for ES_EVENT_TYPE_NOTIFY_OPEN and ES_EVENT_TYPE_NOTIFY_EXEC calls that violate expected entitlement boundaries.
Compare process entitlements (codesign -d --entitlements) against observed file and IPC activity to identify deviations.
Hunt for processes launched from ~/Downloads, /Applications, or /tmp that access sensitive user data shortly after launch.

Monitoring Recommendations

Forward Unified Log entries from com.apple.sandbox and com.apple.securityd to a centralized SIEM for retention and correlation.
Track macOS version inventory across the fleet and flag endpoints not yet upgraded to macOS Tahoe 26.
Alert on Gatekeeper bypass events and notarization failures that often precede sandbox escape attempts.

How to Mitigate CVE-2025-43340

Immediate Actions Required

Upgrade all affected systems to macOS Tahoe 26 as instructed in the Apple Support Document.
Audit installed third-party applications and remove any that are unsigned, unnotarized, or sourced from untrusted distribution channels.
Restrict administrative privileges on user accounts to limit the impact of a successful local escape.

Patch Information

Apple fixed CVE-2025-43340 in macOS Tahoe 26 by adding additional permission restrictions to the affected code path. The vendor advisory is available at the Apple Support Document. No backport to earlier macOS versions is documented in the advisory.

Workarounds

Apply the official update; Apple does not list a supported workaround for this issue.
Enforce application allowlisting via Mobile Device Management (MDM) to block execution of unapproved binaries.
Disable installation of apps from outside the Mac App Store on managed endpoints using MDM configuration profiles.

bash

# Verify the macOS build and confirm the patch is installed
sw_vers
softwareupdate --list
sudo softwareupdate --install --all --restart