CVE-2024-7055: FFmpeg Buffer Overflow Vulnerability

CVE-2024-7055 Overview

A heap-based buffer overflow vulnerability has been identified in FFmpeg versions up to 7.0.1. This vulnerability affects the pnm_decode_frame function located in the /libavcodec/pnmdec.c library, which is responsible for decoding PNM (Portable Any Map) image formats. The vulnerability allows remote attackers to potentially execute arbitrary code or cause denial of service by crafting malicious media files that trigger the heap overflow during decoding operations.

Critical Impact

Remote attackers can exploit this heap-based buffer overflow vulnerability by providing specially crafted media files to FFmpeg, potentially leading to arbitrary code execution or system crashes. A proof-of-concept exploit has been publicly disclosed.

Affected Products

• FFmpeg versions prior to 5.1.6
• FFmpeg versions 6.0 through 6.1.1
• FFmpeg versions 7.0 through 7.0.1

Discovery Timeline

• August 6, 2024 - CVE-2024-7055 published to NVD
• November 3, 2025 - Last updated in NVD database

Technical Details for CVE-2024-7055

Vulnerability Analysis

This vulnerability is classified as a heap-based buffer overflow (CWE-122) and out-of-bounds write (CWE-787). The flaw exists in the PNM decoder component of FFmpeg's libavcodec library. When processing malformed PNM image data, the pnm_decode_frame function fails to properly validate input boundaries, allowing data to be written beyond the allocated heap buffer. This memory corruption can be exploited to overwrite critical heap metadata or adjacent memory structures.

The vulnerability is particularly concerning because FFmpeg is widely used across numerous applications, streaming platforms, and media processing pipelines. Any application that processes untrusted media files using vulnerable FFmpeg versions could be susceptible to exploitation.

Root Cause

The root cause lies in insufficient bounds checking within the pnm_decode_frame function when parsing PNM image dimensions and pixel data. The decoder allocates a heap buffer based on parsed image dimensions but fails to properly validate that the actual pixel data does not exceed the allocated buffer size. This allows an attacker to craft a malicious PNM file with mismatched dimension headers and pixel data to trigger an out-of-bounds write condition.

Attack Vector

The attack can be initiated remotely by providing a specially crafted PNM image file to any application using a vulnerable FFmpeg library. Attack scenarios include:

1. Direct file processing: An attacker sends a malicious media file to a user or uploads it to a service that processes media using FFmpeg
2. Streaming attacks: Malicious content embedded in streaming media that gets decoded by FFmpeg
3. Web applications: Websites or APIs that accept user-uploaded media files and process them with FFmpeg for transcoding or thumbnail generation

The vulnerability is exploitable without authentication and requires no user interaction beyond triggering the file to be processed. A proof-of-concept demonstrating this vulnerability is available on GitHub PoC for CVE.

Detection Methods for CVE-2024-7055

Indicators of Compromise

• Unexpected crashes or segmentation faults in FFmpeg or applications using libavcodec
• Memory corruption errors in system logs when processing PNM image files
• Abnormal heap memory allocation patterns during media file processing
• Unusual process behavior or child process spawning from FFmpeg-dependent applications

Detection Strategies

• Monitor for abnormal termination of FFmpeg processes, particularly SIGSEGV or SIGABRT signals
• Implement file type validation to flag suspicious PNM files with malformed headers before processing
• Deploy endpoint detection rules to identify exploitation attempts targeting FFmpeg's PNM decoder
• Use application-level sandboxing to contain potential exploitation attempts

Monitoring Recommendations

• Enable detailed logging for media processing pipelines to capture processing failures
• Monitor system memory usage for abnormal patterns during media file operations
• Implement file integrity monitoring on systems where FFmpeg processes external media
• Configure alerting for repeated FFmpeg process crashes from the same source

How to Mitigate CVE-2024-7055

Immediate Actions Required

• Upgrade FFmpeg to version 7.0.2 or later immediately on all affected systems
• Audit all applications and services using FFmpeg to identify vulnerable deployments
• Consider temporarily disabling PNM format decoding if not required for operations
• Implement input validation to reject or quarantine suspicious media files before processing

Patch Information

The vulnerability has been addressed in FFmpeg version 7.0.2. Organizations should upgrade to this version or later to remediate the vulnerability. Updated packages are available through the FFmpeg Downloads Page. Debian users should refer to the Debian LTS Security Announcement for distribution-specific package updates.

For detailed vulnerability tracking information, refer to VulDB #273651 Overview.

Workarounds

• Disable PNM decoder in FFmpeg configuration if PNM format support is not required
• Process untrusted media files in isolated sandbox environments with restricted permissions
• Implement strict input validation and file type checking before processing external media
• Use application-level controls to limit FFmpeg's access to system resources

# Rebuild FFmpeg without PNM decoder support (temporary workaround)
./configure --disable-decoder=pnm
make clean && make
make install