CVE-2025-31263: Apple macOS Buffer Overflow Vulnerability

CVE-2025-31263 Overview

CVE-2025-31263 is a critical memory corruption vulnerability affecting Apple macOS that allows a malicious application to corrupt coprocessor memory. The vulnerability stems from improper memory handling within the operating system, which Apple has addressed with improved memory management in macOS Sequoia 15.4.

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), indicating that the flaw involves memory operations that can write data outside intended boundaries, potentially compromising the integrity and availability of the coprocessor subsystem.

Critical Impact

A malicious application can exploit this vulnerability to corrupt coprocessor memory, potentially leading to system instability, data integrity issues, or enabling further exploitation of low-level system components.

Affected Products

• Apple macOS (versions prior to macOS Sequoia 15.4)
• Systems running vulnerable macOS versions with coprocessor components
• All Mac devices with Apple Silicon and Intel-based Macs with secure enclaves

Discovery Timeline

• 2025-05-29 - CVE-2025-31263 published to NVD
• 2025-06-02 - Last updated in NVD database

Technical Details for CVE-2025-31263

Vulnerability Analysis

This memory corruption vulnerability exists in macOS's handling of memory operations related to coprocessor communications. Coprocessors in Apple devices, such as the Secure Enclave Processor (SEP) and other specialized processing units, handle sensitive operations including encryption, biometric data processing, and secure boot validation.

The vulnerability allows an application running on the main processor to corrupt memory regions associated with coprocessor functions. This type of vulnerability is particularly concerning because coprocessors are designed to operate in isolated execution environments, and memory corruption affecting these components could undermine the security guarantees they provide.

The network attack vector indicates that this vulnerability could potentially be triggered remotely through a malicious application or payload delivered over the network, though local application execution appears to be the primary exploitation scenario.

Root Cause

The root cause is improper memory handling (CWE-119) within the macOS kernel or related system components that interface with coprocessor memory. This category of vulnerability typically occurs when:

• Memory boundaries are not properly validated before write operations
• Buffer sizes are incorrectly calculated when copying data to coprocessor-accessible memory regions
• Memory mapping operations between user space and coprocessor memory lack proper bounds checking

Apple's fix involved implementing improved memory handling routines to ensure proper validation and bounds checking when applications interact with coprocessor memory spaces.

Attack Vector

The attack requires a malicious application to be installed and executed on the target macOS system. The application can then leverage the memory handling flaw to write data outside intended memory boundaries, corrupting coprocessor memory regions.

The exploitation scenario involves:

1. An attacker crafts a malicious application that makes specific system calls or memory operations
2. The application triggers the improper memory handling condition
3. Memory corruption occurs in coprocessor-accessible regions
4. The corruption could lead to coprocessor malfunction, data integrity issues, or potential code execution in privileged contexts

Since no verified code examples are available for this vulnerability, technical details regarding specific exploitation methods should be referenced from Apple's Security Advisory.

Detection Methods for CVE-2025-31263

Indicators of Compromise

• Unexpected system crashes or kernel panics related to coprocessor operations
• Anomalous memory access patterns in system logs involving coprocessor interfaces
• Applications attempting unusual system calls related to memory mapping or coprocessor communication
• Secure Enclave or coprocessor-related error messages in system diagnostics

Detection Strategies

• Monitor for applications making suspicious memory operations or system calls targeting coprocessor interfaces
• Implement endpoint detection solutions capable of identifying memory corruption attack patterns
• Review system logs for coprocessor-related errors or unexpected memory access violations
• Deploy behavioral analysis to detect applications exhibiting abnormal memory access patterns

Monitoring Recommendations

• Enable verbose logging for kernel and coprocessor subsystems to capture potential exploitation attempts
• Utilize macOS Unified Logging to monitor for memory-related warnings and errors
• Implement real-time endpoint monitoring for suspicious application behavior
• Configure alerting for repeated system crashes or coprocessor failures

How to Mitigate CVE-2025-31263

Immediate Actions Required

• Update all macOS systems to macOS Sequoia 15.4 or later immediately
• Audit installed applications and remove any untrusted or unnecessary software
• Implement application allowlisting to prevent unauthorized applications from executing
• Enable Gatekeeper and ensure only signed applications from identified developers can run

Patch Information

Apple has released macOS Sequoia 15.4 to address this vulnerability with improved memory handling. The patch is available through standard macOS update mechanisms:

• Software Update: System Preferences/Settings → Software Update
• Vendor Advisory: Apple Support Article HT122373

Organizations should prioritize deployment of this update across all managed macOS endpoints given the critical severity rating.

Workarounds

• Restrict installation of applications to only those from the Mac App Store or identified developers
• Implement strict application control policies using MDM solutions
• Enable System Integrity Protection (SIP) to prevent unauthorized modifications to system components
• Consider network segmentation to limit potential remote exploitation vectors

# Verify macOS version and SIP status
sw_vers
csrutil status

# Check for available updates
softwareupdate --list

# Install available updates
softwareupdate --install --all

# Verify Gatekeeper is enabled
spctl --status