CVE-2026-28844: Apple macOS Path Traversal Vulnerability

CVE-2026-28844 Overview

A file access vulnerability has been identified in Apple macOS that allows attackers to bypass file system protections and access protected parts of the file system. The vulnerability stems from improper input validation in file access handling mechanisms. When exploited, an attacker can gain unauthorized access to sensitive files and directories that should be protected by macOS security controls.

Critical Impact

Attackers may gain access to protected parts of the file system, potentially exposing sensitive user data, system configurations, and confidential information stored on affected macOS systems.

Affected Products

• Apple macOS (versions prior to macOS Tahoe 26.4)

Discovery Timeline

• 2026-03-25 - CVE CVE-2026-28844 published to NVD
• 2026-03-25 - Last updated in NVD database

Technical Details for CVE-2026-28844

Vulnerability Analysis

This vulnerability is classified as an improper input validation issue affecting macOS file system access controls. The flaw allows an attacker to circumvent the file system protections that macOS implements to safeguard sensitive directories and files from unauthorized access.

The vulnerability requires user interaction to exploit, meaning that a victim must take some action (such as opening a malicious file or visiting a crafted website) for the attack to succeed. Once triggered, the attacker can read confidential data from protected file system locations, though the vulnerability does not allow for modification of files or denial of service conditions.

macOS implements multiple layers of file system protection, including Gatekeeper, System Integrity Protection (SIP), and sandboxing. This vulnerability appears to bypass one or more of these protective mechanisms through crafted input that is not properly validated before being used in file access operations.

Root Cause

The root cause of CVE-2026-28844 is improper input validation in macOS file access handling. The system fails to adequately validate or sanitize input used in file system operations, allowing specially crafted input to bypass normal access restrictions. Apple addressed this issue by implementing improved input validation to ensure that file access requests are properly checked against security policies before being processed.

Attack Vector

The attack vector for this vulnerability is network-based, requiring user interaction. An attacker could exploit this vulnerability by:

1. Crafting a malicious file, document, or web content that triggers the vulnerability when processed by the victim's system
2. Distributing the malicious payload via email, website, or other network delivery mechanisms
3. Waiting for the victim to interact with the malicious content
4. Upon successful exploitation, gaining read access to protected file system locations

The vulnerability specifically impacts confidentiality, allowing unauthorized access to sensitive information without affecting system integrity or availability.

Detection Methods for CVE-2026-28844

Indicators of Compromise

• Unexpected file access attempts to protected system directories such as /Library, /System, or user-specific protected folders
• Anomalous process behavior attempting to read files outside normal application sandbox boundaries
• Unusual file system access patterns from applications that typically have restricted file access

Detection Strategies

• Monitor file system access logs for attempts to access protected directories from unexpected processes
• Implement endpoint detection rules to identify applications attempting to bypass sandbox restrictions
• Review Unified Logs for file access violations and sandbox denial messages using log show --predicate 'eventMessage contains "sandbox"'

Monitoring Recommendations

• Enable enhanced file system auditing on critical macOS endpoints
• Deploy endpoint detection and response (EDR) solutions capable of monitoring file access patterns
• Regularly review system logs for anomalous file access behavior, particularly from user-installed applications

How to Mitigate CVE-2026-28844

Immediate Actions Required

• Update all affected macOS systems to macOS Tahoe 26.4 or later immediately
• Review recent file access logs for any signs of exploitation prior to patching
• Ensure System Integrity Protection (SIP) is enabled on all macOS systems
• Limit user exposure to untrusted files and websites until patches are applied

Patch Information

Apple has addressed this vulnerability in macOS Tahoe 26.4 with improved input validation. Organizations should apply this update immediately to protect against potential exploitation. The security update is available through the standard macOS Software Update mechanism or can be downloaded directly from Apple.

For detailed patch information, refer to the Apple Security Advisory.

Workarounds

• Restrict users from opening files or documents from untrusted sources until the patch is applied
• Enable additional browser security controls to limit exposure to web-based attack vectors
• Consider implementing application whitelisting to prevent execution of untrusted applications
• Ensure endpoint protection solutions are updated with the latest detection signatures