CVE-2024-47834: GStreamer Use-After-Free Vulnerability

CVE-2024-47834 Overview

CVE-2024-47834 is a Use-After-Free (UAF) read vulnerability discovered in GStreamer, a widely-used open-source multimedia framework for constructing graphs of media-handling components. The vulnerability specifically affects the processing of CodecPrivate elements in Matroska streams, where freed memory is incorrectly accessed during serialization operations.

Critical Impact

Attackers can exploit this UAF vulnerability through maliciously crafted Matroska media files to read freed memory, potentially leading to information disclosure or application crashes.

Affected Products

• GStreamer versions prior to 1.24.10
• Linux distributions using vulnerable GStreamer packages
• Applications and media players built on GStreamer framework

Discovery Timeline

• 2024-12-12 - CVE CVE-2024-47834 published to NVD
• 2026-03-17 - Last updated in NVD database

Technical Details for CVE-2024-47834

Vulnerability Analysis

This Use-After-Free vulnerability occurs within the Matroska demuxer component of GStreamer. The flaw manifests during the processing of CodecPrivate elements, which are used to store codec-specific initialization data in Matroska container files.

The vulnerability follows a classic UAF pattern where memory is allocated, subsequently freed, and then incorrectly accessed. In the GST_MATROSKA_ID_CODECPRIVATE case within the gst_matroska_demux_parse_stream function, a data chunk is allocated using gst_ebml_read_binary. This allocated memory is later freed in the gst_matroska_track_free function through a call to g_free(track->codec_priv). The critical issue arises when this freed memory is subsequently accessed in the caps_serialize function via gst_value_serialize_buffer.

The vulnerability requires local access to exploit, typically through processing a maliciously crafted Matroska (.mkv or .mka) file. Successful exploitation could result in information disclosure through reading of freed memory contents or denial of service through application crashes.

Root Cause

The root cause is improper memory lifecycle management in the Matroska demuxer. The codec_priv pointer continues to be referenced after the memory it points to has been deallocated. This occurs because:

1. Memory is allocated for codec private data during stream parsing
2. The track structure is freed, including the codec_priv memory
3. The serialization function still holds a reference to the freed memory
4. Accessing this dangling pointer results in undefined behavior

This is classified under CWE-416 (Use After Free), a common vulnerability class in C/C++ applications where memory management must be handled manually.

Attack Vector

The attack requires local access to the target system. An attacker would craft a malicious Matroska media file containing specially structured CodecPrivate elements designed to trigger the vulnerable code path. When a victim processes this file using a GStreamer-based application, the UAF condition is triggered.

The vulnerability mechanism involves the improper ordering of memory operations in the Matroska stream processing pipeline. When CodecPrivate data is parsed, the memory allocation and deallocation sequence creates a window where freed memory remains accessible through stale pointers. The gst_value_serialize_buffer function attempts to serialize buffer contents from memory that has already been returned to the system's memory allocator, leading to the use-after-free condition. For complete technical details, see the GStreamer Security Advisory SA-2024-0030.

Detection Methods for CVE-2024-47834

Indicators of Compromise

• Unexpected crashes in GStreamer-based applications when processing Matroska files
• Memory access violations or segmentation faults in gst_value_serialize_buffer or related functions
• Unusual Matroska files with malformed CodecPrivate elements being processed on the system

Detection Strategies

• Monitor GStreamer applications for abnormal terminations and memory access errors
• Implement file integrity monitoring for incoming media files, particularly Matroska containers
• Use memory debugging tools like AddressSanitizer (ASan) in development environments to detect UAF conditions
• Deploy application-level crash monitoring to identify potential exploitation attempts

Monitoring Recommendations

• Enable detailed logging for media processing applications to capture crash details
• Monitor system logs for GStreamer-related error messages indicating memory corruption
• Implement sandboxing for media processing workloads to limit the impact of potential exploitation
• Track GStreamer package versions across your infrastructure to identify vulnerable installations

How to Mitigate CVE-2024-47834

Immediate Actions Required

• Update GStreamer to version 1.24.10 or later immediately
• Audit systems for vulnerable GStreamer installations using package managers
• Consider restricting processing of untrusted Matroska files until patching is complete
• Implement application sandboxing for media processing workloads

Patch Information

The vulnerability is fixed in GStreamer version 1.24.10. The official patch is available through the GitLab Merge Request 8057. System administrators should update GStreamer packages through their distribution's package manager. Debian users can refer to the Debian LTS Announcement for specific package update instructions.

Workarounds

• Isolate media processing in sandboxed environments to limit potential impact
• Avoid processing Matroska files from untrusted sources until patching is complete
• Use alternative media containers (non-Matroska) for critical workflows if possible
• Implement strict input validation and file type verification before processing

# Update GStreamer on Debian/Ubuntu systems
sudo apt update && sudo apt upgrade gstreamer1.0-plugins-base gstreamer1.0-plugins-good

# Verify installed GStreamer version
gst-inspect-1.0 --version

# On Fedora/RHEL systems
sudo dnf update gstreamer1 gstreamer1-plugins-base