CVE-2026-28827: Apple macOS Path Traversal Vulnerability

CVE-2026-28827 Overview

A critical path traversal vulnerability exists in Apple macOS due to improper validation of directory paths during parsing operations. This flaw allows a malicious application to escape its sandbox environment by exploiting insufficient path validation, potentially gaining unauthorized access to protected system resources and user data outside the sandbox boundary.

Critical Impact

This sandbox escape vulnerability enables malicious applications to break out of macOS security boundaries, potentially accessing sensitive system files, user credentials, and protected application data that should be isolated from sandboxed processes.

Affected Products

• macOS Sequoia versions prior to 15.7.5
• macOS Sonoma versions prior to 14.8.5
• macOS Tahoe versions prior to 26.4

Discovery Timeline

• 2026-03-25 - CVE-2026-28827 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-28827

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as path traversal or directory traversal. The flaw resides in how macOS handles directory path parsing within sandboxed application contexts.

The sandbox mechanism in macOS is designed to restrict applications to specific directories and system resources, preventing unauthorized access to sensitive areas of the operating system. However, the vulnerable path parsing implementation fails to properly validate and sanitize directory paths, allowing specially crafted path sequences to traverse outside the intended sandbox boundaries.

When a sandboxed application submits a directory path for processing, the system should normalize and validate the path to ensure it remains within the application's permitted scope. The vulnerable code fails to adequately handle certain path manipulation techniques, enabling an attacker to construct paths that reference locations outside the sandbox container.

Root Cause

The root cause of CVE-2026-28827 lies in inadequate path validation logic within the directory path handling subsystem. The parsing mechanism does not sufficiently sanitize or canonicalize paths before using them to access file system resources. This allows path traversal sequences and symbolic link manipulations to bypass the sandbox's directory restrictions, ultimately providing access to protected system locations.

Attack Vector

This vulnerability requires local access to execute, meaning an attacker must first have the ability to run a malicious application on the target macOS system. The attack does not require user interaction or elevated privileges to exploit, though the application must be installed and running within a sandbox environment.

An attacker would typically deliver a malicious application through social engineering, compromised software distribution channels, or by embedding the exploit within an otherwise legitimate-appearing application. Once the malicious app is running, it can leverage the path parsing flaw to escape its sandbox and access sensitive resources such as:

• User documents and personal files outside the sandbox
• System configuration files
• Credentials stored by other applications
• Protected application data from other sandboxed apps

The path traversal technique exploits the parsing logic by submitting specially formatted directory paths that bypass validation checks, allowing the application to read or potentially write to locations it should not have access to.

Detection Methods for CVE-2026-28827

Indicators of Compromise

• Unusual file access patterns from sandboxed applications attempting to reach directories outside their container
• Sandbox violation logs in macOS Console showing repeated path-based access attempts
• Unexpected file modifications in protected system directories by applications that should be sandboxed
• Process activity showing sandboxed apps accessing user home directories or system paths

Detection Strategies

• Monitor macOS sandbox violation logs for applications repeatedly attempting unauthorized directory access
• Implement endpoint detection rules to flag sandboxed processes accessing paths outside their designated container
• Review application behavior for anomalous file system access patterns that indicate potential sandbox escape
• Deploy SentinelOne Singularity Platform to detect and block unauthorized sandbox breakout attempts in real-time

Monitoring Recommendations

• Enable verbose sandbox logging in macOS to capture detailed path access attempts
• Configure SIEM alerts for patterns consistent with directory traversal exploitation
• Regularly audit installed applications for suspicious path manipulation behavior
• Monitor for applications that have been flagged in threat intelligence feeds as potentially malicious

How to Mitigate CVE-2026-28827

Immediate Actions Required

• Update all macOS systems to the patched versions: Sequoia 15.7.5, Sonoma 14.8.5, or Tahoe 26.4
• Review installed applications and remove any untrusted or suspicious software
• Enable Gatekeeper and ensure only applications from identified developers are permitted to run
• Implement network segmentation to limit the blast radius if a system is compromised

Patch Information

Apple has released security updates that address this vulnerability through improved path validation. The fixes are available in:

• macOS Sequoia 15.7.5 - Apple Support Advisory #126794
• macOS Sonoma 14.8.5 - Apple Support Advisory #126795
• macOS Tahoe 26.4 - Apple Support Advisory #126796

Organizations should prioritize deployment of these updates to all affected macOS systems. Use Apple's Software Update mechanism or enterprise management tools like Jamf or Kandji to ensure consistent patch deployment across your fleet.

Workarounds

• Restrict application installations to only those from the Mac App Store until patches can be applied
• Implement application allowlisting to prevent unauthorized software from executing
• Use Mobile Device Management (MDM) profiles to enforce stricter application permissions
• Consider temporarily disabling or restricting execution of non-essential third-party applications on sensitive systems

# Verify current macOS version to check patch status
sw_vers -productVersion

# Check for available software updates
softwareupdate --list

# Install all available security updates
sudo softwareupdate --install --all --restart