CVE-2025-43366: Apple macOS Information Disclosure Flaw

CVE-2025-43366 Overview

CVE-2025-43366 is an out-of-bounds read vulnerability in Apple macOS that allows a local application to disclose coprocessor memory. Apple addressed the flaw with improved bounds checking in macOS Tahoe 26. The weakness is tracked under CWE-125 (Out-of-bounds Read).

Exploitation requires local access and user interaction, and the impact is limited to confidentiality of memory contents. No public proof-of-concept, exploit code, or evidence of in-the-wild abuse has been reported at this time.

Critical Impact
A malicious application running locally on an affected macOS system can read coprocessor memory, potentially exposing sensitive data processed outside the main CPU boundary.

Affected Products

Apple macOS versions prior to macOS Tahoe 26
Apple silicon systems using coprocessor subsystems exposed to user-space applications
Applications relying on the vulnerable macOS component for coprocessor interaction

Discovery Timeline

2025-09-15 - CVE-2025-43366 published to the National Vulnerability Database
2025-09-15 - Apple publishes security advisory in support article 125110
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-43366

Vulnerability Analysis

The vulnerability is an out-of-bounds read in a macOS component that mediates access to coprocessor memory. When the component processes attacker-controlled input, it reads data past the end of an allocated buffer. The returned bytes originate from adjacent memory belonging to the coprocessor subsystem.

Because the disclosed region is coprocessor memory, the leaked data may include cryptographic material, intermediate compute state, or other sensitive artifacts processed outside the main CPU. The confidentiality impact is high, while integrity and availability are not affected. Attack complexity is low, but the attacker must already be able to run code on the local system and induce user interaction.

Root Cause

The defect stems from missing or insufficient bounds validation on an index or length value used when reading from a buffer tied to coprocessor memory. Without the check, the code accesses memory outside the intended object. Apple's fix adds explicit bounds checking to constrain read operations to the allocated region.

Attack Vector

An attacker delivers or installs a crafted application on the target macOS device. When a user launches or interacts with the application, it issues requests to the vulnerable component and receives out-of-bounds bytes in response. The attacker then exfiltrates the disclosed memory for offline analysis. No network access, elevated privileges, or authentication is required beyond standard local user execution.

No verified public exploit code is available. See the Apple Support Article and the Full Disclosure Security Bulletin for vendor and community details.

Detection Methods for CVE-2025-43366

Indicators of Compromise

Unsigned or newly installed applications making unexpected calls into macOS coprocessor interfaces
Processes reading unusually large volumes of data from system frameworks associated with coprocessor access
Outbound network transfers immediately following local coprocessor interaction by non-system processes

Detection Strategies

Inventory macOS endpoints and flag hosts running versions earlier than macOS Tahoe 26
Baseline legitimate applications that interact with coprocessor APIs and alert on deviations from that baseline
Correlate application installation events with subsequent anomalous system framework usage

Monitoring Recommendations

Collect endpoint telemetry for process execution, code signing status, and library loads on macOS fleets
Monitor Install.log and MDM logs for unauthorized application deployments
Track macOS software version compliance through management tooling and alert on unpatched hosts

How to Mitigate CVE-2025-43366

Immediate Actions Required

Upgrade all affected systems to macOS Tahoe 26 or later using Apple Software Update
Restrict installation of untrusted third-party applications through Gatekeeper and MDM policy
Enforce code signing and notarization requirements for all applications executed on managed endpoints

Patch Information

Apple addressed CVE-2025-43366 in macOS Tahoe 26 by adding improved bounds checking to the affected component. Full remediation details are published in Apple's advisory at support.apple.com/en-us/125110. Administrators should deploy the update through Apple Software Update, MDM, or Apple Business Manager.

Workarounds

Limit local user accounts to standard privileges and prohibit installation of unverified applications
Enable Gatekeeper enforcement and require notarized applications on all managed macOS devices
Use application allowlisting to prevent execution of unknown binaries until systems are patched

bash

# Verify current macOS version and enforce update compliance
sw_vers -productVersion
softwareupdate --list
sudo softwareupdate --install --all --restart

# Confirm Gatekeeper is enabled
spctl --status