CVE-2026-20618
📋 TL;DR
This macOS vulnerability allows applications to access sensitive user data through improper handling of temporary files. It affects macOS systems before version 26.3. Users running vulnerable macOS versions are at risk of data exposure.
💻 Affected Systems
- macOS
📦 What is this software?
Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →⚠️ Risk & Real-World Impact
Worst Case
Malicious applications could access and exfiltrate sensitive user data including passwords, documents, and personal information stored in temporary files.
Likely Case
Applications with legitimate permissions could inadvertently access or leak sensitive data from temporary files they shouldn't have access to.
If Mitigated
With proper application sandboxing and file permission controls, the impact would be limited to data accessible within the application's designated scope.
🎯 Exploit Status
Exploitation requires a malicious or compromised application to be installed and executed on the target system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Tahoe 26.3
Vendor Advisory: https://support.apple.com/en-us/126348
Restart Required: No
Instructions:
1. Open System Settings 2. Click General 3. Click Software Update 4. Install macOS Tahoe 26.3 update
🔧 Temporary Workarounds
Restrict application permissions
macOSLimit application access to sensitive directories through macOS privacy settings
🧯 If You Can't Patch
- Implement strict application allowlisting to prevent unauthorized applications from running
- Use full disk encryption and ensure sensitive data is stored in encrypted containers
🔍 How to Verify
Check if Vulnerable:
Check macOS version in System Settings > General > About. If version is earlier than 26.3, system is vulnerable.Check Version:
sw_versVerify Fix Applied:
Verify macOS version shows 26.3 or later in System Settings > General > About📡 Detection & Monitoring
Log Indicators:
- Unusual file access patterns in system logs
- Applications accessing temporary files outside their expected scope
Network Indicators:
- Unexpected outbound data transfers from applications
SIEM Query:
process_access_file AND file_path CONTAINS '/tmp/' OR file_path CONTAINS '/var/tmp/'