CVE-2026-20669: Apple macOS Path Traversal Vulnerability

CVE-2026-20669 Overview

CVE-2026-20669 is a path traversal vulnerability (CWE-22) affecting Apple macOS that stems from improper validation of directory paths during parsing operations. The flaw allows a local application to bypass intended access restrictions and read sensitive user data by manipulating directory path inputs. Apple has addressed this issue in macOS Tahoe 26.3 through improved path validation mechanisms.

Critical Impact

A malicious application running on an affected macOS system can exploit improper path validation to access sensitive user data that should otherwise be protected by operating system access controls.

Affected Products

• Apple macOS (versions prior to macOS Tahoe 26.3)

Discovery Timeline

• 2026-02-11 - CVE-2026-20669 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2026-20669

Vulnerability Analysis

This vulnerability exists in macOS's directory path handling mechanism. The root issue involves insufficient validation of user-supplied directory paths, which enables path traversal attacks. When a malicious application provides specially crafted path strings containing traversal sequences (such as ../), the system fails to properly sanitize these inputs before processing them.

The attack requires local access to the system and low privileges to execute. Once exploited, the vulnerability provides unauthorized read access to sensitive user data, though it does not enable modification of files or denial of service conditions. This represents a confidentiality breach where private user information may be exposed to unauthorized applications.

Root Cause

The underlying cause is a parsing error in the handling of directory paths within macOS system components. The path validation routines failed to adequately check for and neutralize directory traversal sequences before accessing filesystem resources. This allowed relative path references to escape intended directory boundaries and access files outside the application's authorized scope.

Attack Vector

The attack vector is local, requiring an attacker to have code execution capability on the target macOS system. This could be achieved through a malicious application downloaded by a user, a compromised legitimate application, or through other local access methods.

The exploitation flow involves:

1. A malicious application crafts a directory path containing traversal sequences
2. The application passes this malformed path to vulnerable macOS parsing functions
3. The system fails to properly validate or sanitize the path
4. The application gains read access to sensitive user data outside its intended scope

Due to the local attack vector, exploitation typically requires social engineering to convince a user to install a malicious application, or the compromise of an existing application on the system.

Detection Methods for CVE-2026-20669

Indicators of Compromise

• Unusual file access patterns from applications attempting to read files outside their sandboxed directories
• Applications making repeated filesystem calls with path traversal sequences (../, ..\)
• Unexpected access to sensitive user directories such as ~/Documents, ~/Library/Keychains, or other protected locations
• Process activity logs showing unauthorized access to user data directories

Detection Strategies

• Monitor filesystem access logs for traversal pattern indicators in path strings
• Implement application behavior monitoring to detect out-of-scope file access attempts
• Deploy endpoint detection solutions capable of identifying path traversal exploitation attempts
• Review system logs for anomalous application behavior involving sensitive data directories

Monitoring Recommendations

• Enable and review macOS Unified Logs for filesystem access anomalies
• Configure SentinelOne agents to monitor for suspicious file access patterns from untrusted applications
• Implement alerts for applications attempting to access sensitive user directories without proper authorization
• Regularly audit installed applications for unexpected filesystem permissions or behaviors

How to Mitigate CVE-2026-20669

Immediate Actions Required

• Update macOS to version Tahoe 26.3 or later immediately
• Review installed applications and remove any untrusted or unnecessary software
• Enable macOS Gatekeeper to restrict application installations to verified sources
• Limit user privileges and enforce application sandboxing where possible

Patch Information

Apple has released a security update addressing this vulnerability in macOS Tahoe 26.3. The fix implements improved path validation to prevent directory traversal attacks. Users should apply this update immediately through System Preferences > Software Update or through enterprise patch management systems.

For detailed information about the security update, refer to the Apple Support Document.

Workarounds

• Restrict application installations to the Mac App Store and identified developers only
• Enable System Integrity Protection (SIP) to limit system-level access for applications
• Utilize macOS sandbox profiles to restrict application filesystem access
• Monitor and audit application behavior using endpoint detection tools until the patch can be applied
• Avoid running untrusted applications or those from unverified sources

# Verify macOS version and SIP status
sw_vers
csrutil status

# Check for pending software updates
softwareupdate --list

# Install available security updates
softwareupdate --install --recommended