CVE-2025-31280: Apple macOS Use-After-Free Vulnerability

CVE-2025-31280 Overview

CVE-2025-31280 is a heap-based memory corruption vulnerability in Apple macOS. Processing a maliciously crafted file triggers heap corruption in an affected component, enabling local code execution within the user's context. Apple addressed the issue with improved validation in macOS Sequoia 15.6.

The flaw is classified under [CWE-122] (Heap-based Buffer Overflow). Exploitation requires user interaction, such as opening a crafted file, but does not require prior authentication. Successful exploitation impacts confidentiality, integrity, and availability of the affected system.

Critical Impact
A user opening a maliciously crafted file on an unpatched macOS system can experience heap corruption that may lead to arbitrary code execution in the current user's security context.

Affected Products

Apple macOS versions prior to Sequoia 15.6
Systems processing untrusted files on vulnerable macOS builds
Endpoints where file preview, parsing, or document handling features are enabled

Discovery Timeline

2025-07-30 - CVE-2025-31280 published to NVD
2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-31280

Vulnerability Analysis

The vulnerability resides in macOS file processing logic that fails to properly validate input before allocating or writing to heap memory. When the affected component parses a maliciously crafted file, attacker-controlled data corrupts adjacent heap structures. This corruption can overwrite function pointers, object metadata, or allocator bookkeeping fields.

Apple's advisory states the issue was resolved with improved validation. The fix shipped in macOS Sequoia 15.6. Apple has not published the specific component, file format, or parsing routine involved in its public bulletin.

Exploitation is local and requires the victim to open or otherwise process the malicious file. Attackers typically deliver such files through phishing, drive-by downloads, or messaging platforms. Code execution occurs at the privilege level of the user processing the file.

Root Cause

The root cause is insufficient input validation during file parsing. The vulnerable code path trusts attributes encoded in the file (such as length fields, offsets, or structural counts) without verifying them against allocated buffer boundaries. This leads to a heap-based buffer overflow [CWE-122].

Attack Vector

An attacker crafts a malicious file targeting the vulnerable parser. The file is delivered to the victim via email, web download, removable media, or collaboration tools. When the user opens or previews the file on an unpatched macOS system, the parser corrupts heap memory. Refer to the Apple Support Article and the Full Disclosure Mailing List Post for additional context.

Detection Methods for CVE-2025-31280

Indicators of Compromise

Unexpected crashes or EXC_BAD_ACCESS reports in macOS Diagnostic logs tied to file-handling processes
Crash logs in ~/Library/Logs/DiagnosticReports/ referencing heap corruption signatures such as malloc: *** error for object
Files with anomalous structural fields received from untrusted sources prior to a process crash

Detection Strategies

Monitor endpoint telemetry for repeated crashes of document, media, or preview-related processes on macOS hosts
Correlate file open events with subsequent process termination signals or child process spawns
Inspect inbound files from email and web channels using sandboxed analysis to identify malformed structures

Monitoring Recommendations

Track macOS build numbers across the fleet and alert on hosts running versions earlier than Sequoia 15.6
Forward ReportCrash and spindump artifacts to a central log platform for retrospective hunting
Baseline normal file-handler behavior and flag deviations such as unexpected network connections after a file open

How to Mitigate CVE-2025-31280

Immediate Actions Required

Update all macOS endpoints to macOS Sequoia 15.6 or later using Software Update or MDM-managed deployment
Identify unmanaged or out-of-compliance Macs through asset inventory and prioritize remediation
Restrict opening of files from untrusted sources until patching is complete

Patch Information

Apple released the fix in macOS Sequoia 15.6. The patch introduces improved validation in the affected parsing logic. Administrators should consult the Apple Support Article for the complete list of addressed CVEs and verify build numbers post-deployment.

Workarounds

Disable automatic file previews in Finder and Quick Look for files originating from untrusted sources
Enforce email and web gateway policies that strip or quarantine high-risk attachments
Apply application allowlisting and Gatekeeper enforcement to limit execution of unsigned binaries delivered alongside crafted files
Educate users to avoid opening unsolicited files until macOS patching is verified

bash

# Verify the installed macOS version meets the patched build
sw_vers -productVersion
# Expected output: 15.6 or later

# Trigger a software update check from the command line
sudo softwareupdate -l
sudo softwareupdate -ia --restart