CVE-2024-40848: Apple macOS Information Disclosure Flaw

CVE-2024-40848 Overview

CVE-2024-40848 is an information disclosure vulnerability affecting multiple versions of Apple macOS. The issue stems from a downgrade weakness that Apple addressed by introducing additional code-signing restrictions. An attacker exploiting this flaw may be able to read sensitive information from a vulnerable system. The vulnerability impacts macOS Ventura, macOS Sonoma, and earlier releases of macOS Sequoia. Apple resolved the issue in macOS Sequoia 15, macOS Sonoma 14.7, and macOS Ventura 13.7. The Apple advisories referenced in the National Vulnerability Database (NVD) entry document the patches across affected macOS branches.

Critical Impact

An unauthenticated network attacker can leverage the code-signing downgrade weakness to read sensitive information from an unpatched macOS host.

Affected Products

• Apple macOS Ventura prior to 13.7
• Apple macOS Sonoma prior to 14.7
• Apple macOS Sequoia prior to 15

Discovery Timeline

• 2024-09-17 - CVE-2024-40848 published to the National Vulnerability Database (NVD)
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2024-40848

Vulnerability Analysis

CVE-2024-40848 is categorized as a downgrade vulnerability that intersects with macOS code-signing enforcement. Apple's advisory text states the issue was addressed with additional code-signing restrictions. The flaw enables an attacker to coerce the system into accepting a less secure state, which exposes sensitive information. The CWE classification in the NVD entry is NVD-CWE-noinfo, indicating Apple did not publicly disclose underlying weakness specifics. The Environmental Protection Scoring System (EPSS) rates the probability of exploitation at 0.149% with a percentile of 35.104.

Root Cause

The root cause is insufficient enforcement preventing macOS components from operating with older or weaker code-signing constraints. Without the additional restrictions introduced in the patch, signed components could be downgraded to a state where security checks did not adequately protect sensitive data. Apple's fix tightens code-signing validation to block the downgrade path.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker reaches the vulnerable code paths on a target macOS host and triggers the downgrade condition. Successful exploitation discloses sensitive information stored or processed by affected system components. Integrity and availability are not impacted, only confidentiality. Apple has not published exploitation details, and there are no public proof-of-concept exploits listed for this CVE.

No verified exploit code is available. See the Apple Support Article #121234, Apple Support Article #121238, and Apple Support Article #121247 for vendor-published technical details.

Detection Methods for CVE-2024-40848

Indicators of Compromise

• No public indicators of compromise have been published for CVE-2024-40848.
• Apple has not released telemetry or forensic markers tied to exploitation of this flaw.

Detection Strategies

• Inventory macOS endpoints and identify hosts running versions earlier than macOS Ventura 13.7, macOS Sonoma 14.7, or macOS Sequoia 15.
• Audit code-signing validation events and unexpected loading of older signed binaries on macOS endpoints.
• Correlate network telemetry against macOS hosts that have not yet received the September 2024 security updates.

Monitoring Recommendations

• Track patch deployment status across the macOS fleet using mobile device management (MDM) reporting.
• Monitor system.log and unified logging for anomalous code-signing or amfid events on unpatched hosts.
• Alert on processes that attempt to load components with older or revoked code-signing requirements.

How to Mitigate CVE-2024-40848

Immediate Actions Required

• Upgrade affected systems to macOS Sequoia 15, macOS Sonoma 14.7, or macOS Ventura 13.7 as published by Apple.
• Prioritize patching for macOS endpoints exposed to untrusted networks, since the attack vector is network-based.
• Verify patch status through MDM compliance reporting after deployment.

Patch Information

Apple released fixes in macOS Sequoia 15, macOS Sonoma 14.7, and macOS Ventura 13.7. Refer to Apple Support Article #121234, Apple Support Article #121238, and Apple Support Article #121247 for the corresponding security content notes. Additional discussion is archived in the Full Disclosure Mailing List Post 33, Full Disclosure Mailing List Post 40, and Full Disclosure Mailing List Post 41.

Workarounds

• No vendor-supplied workarounds exist; applying the official Apple updates is the only supported remediation.
• Restrict exposure of unpatched macOS endpoints to untrusted networks until updates are applied.
• Enforce least-privilege configurations and disable unnecessary network-facing services on macOS hosts pending patch deployment.

# Verify installed macOS version and apply pending Apple updates
sw_vers -productVersion
sudo softwareupdate --list
sudo softwareupdate --install --all --restart