CVE-2025-1373: FFmpeg Use-After-Free Vulnerability

CVE-2025-1373 Overview

A null pointer dereference vulnerability has been identified in FFmpeg versions up to 7.1. This security flaw exists within the mov_read_trak function in the libavformat/mov.c file, which is part of FFmpeg's MOV Parser component. When processing specially crafted media files, the vulnerability can be triggered through manipulation that leads to a null pointer dereference condition.

Critical Impact

Local attackers with access to the system can exploit this vulnerability to cause a denial of service condition by crashing the FFmpeg process during media file parsing.

Affected Products

• FFmpeg versions up to 7.1
• Applications and services that integrate FFmpeg's libavformat library
• Media processing pipelines utilizing FFmpeg's MOV Parser functionality

Discovery Timeline

• 2025-02-17 - CVE-2025-1373 published to NVD
• 2025-06-03 - Last updated in NVD database

Technical Details for CVE-2025-1373

Vulnerability Analysis

This vulnerability represents a null pointer dereference issue within FFmpeg's MOV file format parser. The mov_read_trak function, responsible for parsing track atoms in MOV/MP4 container files, fails to properly validate pointer references before dereferencing them. When processing a malformed or maliciously crafted media file, the parser may encounter an unexpected null pointer, leading to an application crash.

The MOV Parser component is a critical part of FFmpeg's libavformat library, handling the demuxing of QuickTime Movie (MOV) and MPEG-4 Part 14 (MP4) container formats. Due to the complexity of these container formats and the various atom structures they can contain, robust null pointer checking is essential to prevent crashes during parsing operations.

The vulnerability requires local access to exploit, meaning an attacker would need to either have local system access or convince a user to process a malicious media file. The exploit has been publicly disclosed, increasing the risk of exploitation.

Root Cause

The root cause of this vulnerability lies in improper resource management (CWE-404) within the mov_read_trak function. The code path fails to include adequate null pointer validation before accessing memory through pointer references. When the parser encounters unexpected or malformed data in the track atom structure, it may attempt to dereference a null pointer, resulting in a crash.

The vulnerability specifically manifests in the libavformat/mov.c file, where track parsing logic does not account for all edge cases that could result in null pointer conditions.

Attack Vector

This is a local attack vector vulnerability. To exploit this flaw, an attacker must:

1. Craft a malicious MOV or MP4 file with specific structures that trigger the null pointer condition
2. Have the target system process the malicious file using FFmpeg or an application built on FFmpeg's libraries

The attack does not require elevated privileges but does require the attacker to have local access to the system or the ability to deliver a malicious media file to a user or automated processing system.

A proof-of-concept demonstrating this vulnerability has been made available through FFmpeg's bug tracking system. The malicious input triggers the null pointer dereference when processed by vulnerable FFmpeg versions.

Detection Methods for CVE-2025-1373

Indicators of Compromise

• Unexpected FFmpeg process crashes when processing MOV/MP4 files
• Application crashes in media processing pipelines that utilize FFmpeg
• Crash dumps referencing mov_read_trak function in libavformat/mov.c
• Segmentation fault signals (SIGSEGV) associated with FFmpeg processes

Detection Strategies

• Monitor for FFmpeg process termination events with abnormal exit codes
• Implement file integrity monitoring for incoming media files before processing
• Deploy application crash monitoring for services utilizing FFmpeg libraries
• Review system logs for repeated crashes in media processing components

Monitoring Recommendations

• Enable core dump collection for FFmpeg processes to aid in forensic analysis
• Implement rate limiting for media file processing to mitigate potential DoS attacks
• Monitor CPU and memory usage patterns for anomalies during media file processing
• Configure alerting for segmentation faults in FFmpeg-dependent applications

How to Mitigate CVE-2025-1373

Immediate Actions Required

• Apply the official FFmpeg patch identified by commit hash 43be8d07281caca2e88bfd8ee2333633e1fb1a13
• Update FFmpeg to a patched version that includes the security fix
• Review and restrict access to media processing systems where possible
• Implement input validation for media files before processing with FFmpeg

Patch Information

The FFmpeg development team has released a patch to address this vulnerability. The fix is identified by commit hash 43be8d07281caca2e88bfd8ee2333633e1fb1a13 and is available in the FFmpeg Git repository.

Organizations should update their FFmpeg installations by either applying this specific patch or upgrading to a version that includes the fix. For detailed information about the vulnerability, refer to FFmpeg Ticket #11460.

Workarounds

• Restrict FFmpeg usage to trusted media files only until patching is complete
• Implement sandboxing or containerization for FFmpeg processing to limit crash impact
• Consider using alternative media processing tools temporarily for untrusted content
• Deploy process supervision to automatically restart crashed FFmpeg instances

# Configuration example
# Apply the FFmpeg security patch
cd /path/to/ffmpeg/source
git fetch origin
git cherry-pick 43be8d07281caca2e88bfd8ee2333633e1fb1a13
make clean
./configure --prefix=/usr/local
make -j$(nproc)
sudo make install