CVE-2025-1594: FFmpeg Buffer Overflow Vulnerability

CVE-2025-1594 Overview

A critical stack-based buffer overflow vulnerability has been identified in FFmpeg versions up to 7.1. The flaw exists within the ff_aac_search_for_tns function located in the libavcodec/aacenc_tns.c file of the AAC Encoder component. This vulnerability can be exploited remotely through specially crafted media files, potentially allowing attackers to execute arbitrary code or cause denial of service conditions on affected systems.

Critical Impact

Remote attackers can exploit this stack-based buffer overflow in FFmpeg's AAC encoder to potentially achieve code execution or crash applications processing malicious audio files.

Affected Products

• FFmpeg versions up to and including 7.1
• Applications and systems using FFmpeg for audio/video processing
• Media servers and transcoding pipelines incorporating vulnerable FFmpeg versions

Discovery Timeline

• 2025-02-23 - CVE-2025-1594 published to NVD
• 2025-06-03 - Last updated in NVD database

Technical Details for CVE-2025-1594

Vulnerability Analysis

This vulnerability affects FFmpeg's AAC (Advanced Audio Coding) encoder, specifically within the Temporal Noise Shaping (TNS) search functionality. The ff_aac_search_for_tns function in libavcodec/aacenc_tns.c fails to properly validate input boundaries before performing memory operations, leading to a stack-based buffer overflow condition.

When processing maliciously crafted audio data, the vulnerable function can write beyond the allocated stack buffer boundaries. This memory corruption can be triggered remotely by convincing a victim to process a specially crafted audio file or stream. The exploit has been publicly disclosed, increasing the risk of exploitation in the wild.

The vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-787 (Out-of-bounds Write), indicating fundamental issues with memory boundary validation in the affected code path.

Root Cause

The root cause of this vulnerability stems from improper bounds checking within the ff_aac_search_for_tns function. During the TNS coefficient search process in AAC encoding, the function does not adequately validate the size of data being written to stack-allocated buffers. This allows an attacker to craft input that causes the function to write beyond the allocated buffer space, corrupting adjacent stack memory including potential return addresses and saved registers.

Attack Vector

The attack can be initiated remotely through the network attack vector. An attacker can exploit this vulnerability by:

1. Crafting a malicious audio file with specially structured data designed to trigger the overflow
2. Distributing the malicious file through various channels (web downloads, email attachments, streaming services)
3. When a victim's application uses the vulnerable FFmpeg library to encode or process the audio, the buffer overflow is triggered
4. The memory corruption can potentially lead to arbitrary code execution or application crash

A proof-of-concept for this vulnerability has been made available through the FFmpeg bug tracking system, demonstrating the exploitability of this flaw.

Detection Methods for CVE-2025-1594

Indicators of Compromise

• Unexpected crashes in FFmpeg or applications using FFmpeg during audio encoding operations
• Segmentation faults or stack smashing detected errors in process logs
• Unusual memory access patterns when processing AAC audio encoding tasks
• Application core dumps indicating stack corruption in libavcodec components

Detection Strategies

• Monitor for abnormal termination of FFmpeg processes, particularly those performing AAC encoding
• Implement file integrity monitoring for systems processing untrusted media files
• Deploy memory protection mechanisms such as stack canaries and ASLR to detect exploitation attempts
• Review application logs for repeated crashes during audio processing operations

Monitoring Recommendations

• Enable enhanced logging for media processing pipelines to capture encoding failures
• Monitor system logs for stack buffer overflow detection messages
• Implement runtime application self-protection (RASP) for critical media processing systems
• Set up alerting for unusual patterns in FFmpeg process behavior and resource consumption

How to Mitigate CVE-2025-1594

Immediate Actions Required

• Upgrade FFmpeg to a patched version beyond 7.1 when available from the vendor
• Restrict processing of untrusted audio files through vulnerable FFmpeg installations
• Implement input validation and sandboxing for media processing workflows
• Consider temporarily disabling AAC encoding functionality in critical systems until patched

Patch Information

Users should monitor the FFmpeg official website and the FFmpeg ticket tracking system for official patch releases. The vulnerability affects FFmpeg versions up to 7.1, and users should upgrade to the latest available version that addresses this issue once released.

Additional technical information and vulnerability tracking can be found at VulDB #296589.

Workarounds

• Sandbox FFmpeg processes using containerization or process isolation technologies
• Implement strict input validation to reject malformed or suspicious audio files before processing
• Use alternative audio encoding libraries for critical applications until a patch is available
• Deploy web application firewalls or content filtering to block potentially malicious media files from reaching vulnerable systems

# Example: Running FFmpeg in a sandboxed environment using firejail
firejail --noprofile --net=none --private ffmpeg -i input.wav -c:a aac output.m4a

# Example: Using docker to isolate FFmpeg processing
docker run --rm -v /path/to/files:/data ffmpeg-sandbox ffmpeg -i /data/input.wav -c:a aac /data/output.m4a