CVE-2026-20629: macOS Tahoe Information Disclosure Flaw

CVE-2026-20629 Overview

CVE-2026-20629 is a privacy vulnerability in macOS Tahoe that stems from improper handling of temporary files. This security flaw allows a malicious application to potentially access user-sensitive data through exploitation of temporary file management mechanisms. Apple has addressed this vulnerability with improved handling of temporary files in macOS Tahoe 26.3.

Critical Impact

Applications may be able to access user-sensitive data through improper temporary file handling, potentially exposing private information to unauthorized parties.

Affected Products

• macOS Tahoe (versions prior to 26.3)

Discovery Timeline

• February 11, 2026 - CVE-2026-20629 published to NVD
• February 12, 2026 - Last updated in NVD database

Technical Details for CVE-2026-20629

Vulnerability Analysis

This vulnerability represents an information disclosure issue within macOS Tahoe's temporary file handling subsystem. The flaw exists in how the operating system manages temporary files, potentially allowing applications to access data they should not have permission to read.

Temporary files in macOS are used extensively by applications for caching, inter-process communication, and storing intermediate data during operations. When these files are not properly secured with appropriate permissions or are stored in predictable locations without adequate access controls, malicious applications can exploit this weakness to read sensitive user data.

The vulnerability was remediated by Apple through improved handling mechanisms for temporary files, likely including better permission enforcement, more secure file locations, and enhanced cleanup routines.

Root Cause

The root cause of this vulnerability lies in improper handling of temporary files within macOS Tahoe. This typically involves one or more of the following issues:

• Temporary files created with overly permissive access rights
• Predictable temporary file paths allowing unauthorized access
• Insufficient isolation between application temporary file spaces
• Race conditions in temporary file creation or cleanup processes

Attack Vector

An attacker would need to deploy a malicious application on the target macOS system. Once installed and running, the malicious application could exploit the improper temporary file handling to:

1. Monitor temporary file locations for sensitive data
2. Read temporary files created by other applications
3. Access cached user credentials or session data
4. Extract private information stored in temporary locations

This attack requires local access through a malicious application and does not appear to be remotely exploitable. The vulnerability primarily impacts user privacy and data confidentiality.

Detection Methods for CVE-2026-20629

Indicators of Compromise

• Unusual application access patterns to /tmp, /var/folders, or other temporary directories
• Applications reading temporary files created by other processes
• Unexpected file system access events in macOS system logs
• Anomalous data exfiltration attempts following temporary file access

Detection Strategies

• Monitor file system access events using macOS Endpoint Security framework
• Implement application behavior analysis to detect unauthorized file access patterns
• Deploy endpoint detection rules for suspicious temporary directory enumeration
• Review application entitlements and sandbox violations

Monitoring Recommendations

• Enable comprehensive file access auditing on macOS endpoints
• Configure SentinelOne agents to monitor for suspicious file system operations
• Establish baseline behavior for legitimate temporary file access patterns
• Alert on applications accessing temporary files outside their sandbox scope

How to Mitigate CVE-2026-20629

Immediate Actions Required

• Update to macOS Tahoe 26.3 or later immediately
• Review installed applications for potentially malicious software
• Audit recent application installations from untrusted sources
• Enable Gatekeeper and ensure only notarized applications are permitted

Patch Information

Apple has released macOS Tahoe 26.3 which addresses this vulnerability with improved handling of temporary files. The security update is available through:

• System Preferences > Software Update
• Apple Security Advisory

Organizations should prioritize deployment of this update across all managed macOS devices to eliminate the privacy risk associated with this vulnerability.

Workarounds

• Restrict application installations to trusted sources only (Mac App Store and identified developers)
• Enable macOS application sandbox enforcement where possible
• Implement strict endpoint security policies using SentinelOne to monitor file access
• Remove or quarantine untrusted applications until patching is complete
• Consider enabling FileVault full-disk encryption to protect data at rest