CVE-2026-20632: Apple macOS Path Traversal Vulnerability

CVE-2026-20632 Overview

A parsing issue in the handling of directory paths has been identified in Apple macOS. The vulnerability stems from improper path validation that could allow a malicious application to bypass directory access controls and access sensitive user data. Apple has addressed this issue with improved path validation in macOS Tahoe 26.4.

Critical Impact

A local application may be able to access sensitive user data by exploiting improper directory path validation, potentially leading to unauthorized disclosure of private information.

Affected Products

• Apple macOS (versions prior to macOS Tahoe 26.4)

Discovery Timeline

• 2026-03-25 - CVE-2026-20632 published to NVD
• 2026-03-25 - Last updated in NVD database

Technical Details for CVE-2026-20632

Vulnerability Analysis

This vulnerability is classified under CWE-284 (Improper Access Control). The flaw exists in how macOS parses and validates directory paths when applications request access to file system resources. Due to insufficient path validation, an attacker can craft malicious path inputs that bypass the intended access restrictions.

The vulnerability allows network-based exploitation without requiring user interaction or special privileges. However, the impact is limited to confidentiality concerns, with no direct impact on system integrity or availability. An attacker exploiting this vulnerability could potentially read sensitive user data that should otherwise be protected by macOS sandboxing and permission controls.

Root Cause

The root cause of this vulnerability is improper validation of directory path inputs during the parsing phase. When applications construct or manipulate file paths, the system fails to properly sanitize or validate certain path components, allowing path traversal or path manipulation techniques to access restricted directories.

The underlying issue relates to how the path parser handles special characters, symbolic links, or path normalization, enabling an application to reference directories outside its intended sandbox or access scope.

Attack Vector

An attacker would need to deploy a malicious application on the target macOS system. The application could then exploit the path parsing vulnerability to:

1. Construct specially crafted directory paths that bypass validation checks
2. Access sensitive user data stored in protected directories
3. Exfiltrate private information such as documents, credentials, or application data

The attack can be conducted remotely if the attacker can convince a user to install the malicious application, though local access simplifies exploitation. The attack requires no user interaction once the malicious app is installed and running.

Detection Methods for CVE-2026-20632

Indicators of Compromise

• Unusual file access patterns by applications attempting to read from protected user directories
• Applications accessing directories outside their expected sandbox scope
• Unexpected path traversal sequences in application file access logs
• Anomalous process behavior involving path manipulation or directory enumeration

Detection Strategies

• Monitor file system access events for applications attempting to access sensitive directories such as ~/Documents, ~/Desktop, or ~/Library
• Implement endpoint detection rules that flag unusual path patterns containing traversal sequences or symbolic link exploitation
• Review application entitlements and sandbox profiles for violations or unexpected file system access
• Deploy behavioral analysis to detect applications reading user data inconsistent with their stated functionality

Monitoring Recommendations

• Enable unified logging for file system access events on macOS endpoints
• Configure security information and event management (SIEM) solutions to alert on suspicious file access patterns
• Monitor for applications with excessive file system permissions or those bypassing Transparency, Consent, and Control (TCC) prompts
• Regularly audit installed applications for known vulnerabilities and unauthorized software

How to Mitigate CVE-2026-20632

Immediate Actions Required

• Update all affected macOS systems to macOS Tahoe 26.4 or later immediately
• Review installed applications and remove any untrusted or unnecessary software
• Enable macOS Gatekeeper and ensure only notarized applications can run
• Verify that System Integrity Protection (SIP) is enabled on all endpoints
• Restrict application installation to trusted sources only (Mac App Store or identified developers)

Patch Information

Apple has released macOS Tahoe 26.4 which addresses this vulnerability with improved path validation. The security update is available through Software Update or from the Apple Security Advisory.

Organizations should prioritize deployment of this update across all managed macOS devices. Enterprise environments can use Mobile Device Management (MDM) solutions to enforce timely patching.

Workarounds

• Restrict installation of third-party applications to only those from verified and trusted sources
• Enable strict application firewall rules to limit network access for untrusted applications
• Review and audit TCC permissions granted to applications, revoking unnecessary access to sensitive directories
• Consider implementing application allowlisting to prevent unauthorized software execution

# Verify macOS version to ensure patch is applied
sw_vers

# Check System Integrity Protection status
csrutil status

# Review TCC database permissions (requires Full Disk Access)
sqlite3 ~/Library/Application\ Support/com.apple.TCC/TCC.db "SELECT client,service FROM access"