CVE-2026-20648: macOS Tahoe Information Disclosure Flaw

CVE-2026-20648 Overview

CVE-2026-20648 is an information disclosure vulnerability in macOS Tahoe that allows a malicious application to access notifications from other iCloud devices. The vulnerability stems from sensitive data being stored in an unprotected location, enabling unauthorized access to private user information across synced Apple devices.

Critical Impact

A malicious app installed on a compromised macOS system can read notifications synced from other iCloud-connected devices, potentially exposing sensitive personal information, two-factor authentication codes, and private communications.

Affected Products

• macOS Tahoe versions prior to 26.3

Discovery Timeline

• 2026-02-11 - CVE-2026-20648 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2026-20648

Vulnerability Analysis

This vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). The core issue involves sensitive notification data from iCloud-connected devices being stored in a location accessible to applications without proper authorization checks. This represents a significant privacy breach as iCloud notification mirroring allows users to receive notifications from their iPhone, iPad, and other Apple devices on their Mac.

The attack requires local access and user interaction to exploit. An attacker would need to convince a user to install and run a malicious application on their macOS system. Once executed, the malicious app can access the unprotected storage location where iCloud notification data resides, bypassing the expected privacy boundaries between applications and system services.

Root Cause

The root cause is improper data protection where sensitive iCloud notification data was stored in a location that lacked appropriate access controls. Apple's fix involved relocating this sensitive data to a protected location with proper permission enforcement, ensuring that only authorized system components can access cross-device notification information.

Attack Vector

The attack vector is local, requiring the attacker to have the ability to execute code on the target macOS system. The exploitation scenario involves:

1. An attacker crafts a malicious macOS application designed to read notification data
2. The victim is socially engineered into downloading and running the malicious application
3. The application accesses the unprotected storage location containing iCloud notification data
4. Sensitive information from notifications across all synced iCloud devices is exposed to the attacker

This vulnerability is particularly concerning because iCloud notifications can contain highly sensitive data including one-time passwords, private messages, banking alerts, and other confidential communications.

Detection Methods for CVE-2026-20648

Indicators of Compromise

• Unusual file access patterns to iCloud-related directories and notification storage locations
• Unexpected applications requesting or accessing notification-related system resources
• Suspicious third-party applications with unexplained access to user data containers
• Anomalous process activity involving notification framework components

Detection Strategies

• Monitor for unauthorized access attempts to notification data storage locations
• Implement application allowlisting to prevent execution of untrusted software
• Review installed applications for unknown or suspicious entries
• Utilize endpoint detection tools to identify malicious data access patterns

Monitoring Recommendations

• Enable enhanced logging for file system access on macOS endpoints
• Configure SentinelOne agents to monitor for suspicious application behavior targeting system data
• Implement alerts for applications accessing sensitive iCloud-related directories
• Review system integrity and application authorization regularly

How to Mitigate CVE-2026-20648

Immediate Actions Required

• Update macOS to version Tahoe 26.3 or later immediately
• Review installed applications and remove any untrusted or unknown software
• Enable Gatekeeper and only allow applications from the App Store or identified developers
• Audit recent application installations for suspicious activity

Patch Information

Apple has addressed this vulnerability in macOS Tahoe 26.3 by relocating sensitive notification data to a protected storage location with proper access controls. Users should update their systems through System Settings > General > Software Update. For detailed information about the security update, refer to the Apple Support Article.

Workarounds

• Restrict application installations to only those from the Mac App Store until the patch is applied
• Disable iCloud notification mirroring temporarily in System Settings > Notifications if unable to update immediately
• Use application sandboxing and permission controls to limit data access for installed applications
• Consider enabling FileVault full-disk encryption for additional data protection at rest