CVE-2026-2921: GStreamer RIFF Palette RCE Vulnerability

CVE-2026-2921 Overview

GStreamer RIFF Palette Integer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of GStreamer. Interaction with this library is required to exploit this vulnerability but attack vectors may vary depending on the implementation.

The specific flaw exists within the handling of palette data in AVI files. The issue results from the lack of proper validation of user-supplied data, which can result in an integer overflow before writing to memory. An attacker can leverage this vulnerability to execute code in the context of the current process.

Critical Impact

Remote code execution through maliciously crafted AVI files targeting the GStreamer multimedia framework, potentially compromising any application that processes media content using GStreamer.

Affected Products

• GStreamer (all vulnerable versions)
• Applications utilizing GStreamer for media processing
• Systems with GStreamer libraries for AVI file handling

Discovery Timeline

• 2026-03-16 - CVE-2026-2921 published to NVD
• 2026-03-17 - Last updated in NVD database

Technical Details for CVE-2026-2921

Vulnerability Analysis

This vulnerability (tracked as ZDI-CAN-28854) is classified as CWE-190: Integer Overflow or Wraparound. The flaw resides in GStreamer's RIFF (Resource Interchange File Format) parser, specifically within the code responsible for handling palette data embedded in AVI container files.

When processing palette information, the vulnerable code fails to properly validate the size of user-supplied data before performing arithmetic operations. This oversight allows an attacker to supply carefully crafted values that cause an integer overflow during memory size calculations. The resulting incorrect memory allocation size leads to a heap buffer overflow condition when the actual palette data is subsequently written to the undersized buffer.

The vulnerability requires user interaction—a victim must open or process a malicious AVI file—but given the prevalence of GStreamer in Linux desktop environments, media players, and web browsers, the attack surface is substantial. Applications that automatically preview or thumbnail video files are particularly at risk.

Root Cause

The root cause is insufficient validation of user-supplied palette size values in AVI file headers before they are used in memory allocation calculations. When large values are processed, the integer multiplication or addition operations overflow, wrapping around to a small value. This results in allocating a buffer that is too small to hold the actual data, leading to a heap-based buffer overflow when the palette data is copied into memory.

Attack Vector

The attack vector is local, requiring the victim to process a maliciously crafted AVI file. Attack scenarios include:

• Opening a malicious AVI file in a media player using GStreamer
• Processing malicious video content through GStreamer-based transcoding or thumbnail generation services
• Automated preview generation systems that process uploaded video files
• Web browsers or applications with GStreamer plugins that handle embedded media content

The attacker crafts an AVI file with a specially designed RIFF palette chunk containing oversized values that trigger the integer overflow. When the victim's GStreamer-based application processes this file, the overflow occurs, enabling potential arbitrary code execution within the context of the running process.

Detection Methods for CVE-2026-2921

Indicators of Compromise

• Unexpected crashes or memory errors in GStreamer-based applications during AVI file processing
• Anomalous process behavior from media players or GStreamer components following media file access
• Suspicious AVI files with malformed RIFF palette chunks or unusually large header values
• Memory corruption artifacts or heap allocation anomalies in GStreamer library processes

Detection Strategies

• Monitor for abnormal GStreamer process behavior including unexpected memory allocation patterns
• Implement file inspection rules for AVI files with suspiciously large palette size declarations in RIFF headers
• Deploy application-level monitoring on media processing pipelines to detect exploitation attempts
• Use memory protection tools to detect heap overflow conditions in GStreamer processes

Monitoring Recommendations

• Enable crash reporting and memory error logging for all GStreamer-based applications
• Implement network monitoring for transfer of suspicious AVI files to critical systems
• Monitor endpoint detection logs for signs of code execution following media file access
• Track GStreamer library loading and function calls in security-sensitive environments

How to Mitigate CVE-2026-2921

Immediate Actions Required

• Apply the official GStreamer security patch immediately
• Restrict processing of untrusted AVI files until patching is complete
• Implement content filtering to block potentially malicious AVI files from untrusted sources
• Review and audit systems that automatically process user-uploaded video content

Patch Information

The GStreamer project has released a fix for this vulnerability. The patch is available through the GitLab commit e3a99c35266fc92dd6a18ac5fde028d0cda559e6. Organizations should update to patched versions of GStreamer through their distribution's package manager or by building from source with this commit applied.

For additional technical details about this vulnerability, refer to the Zero Day Initiative Advisory ZDI-26-168.

Workarounds

• Disable or remove GStreamer AVI parsing plugins (gst-plugins-good containing avidemux) if AVI support is not required
• Implement strict input validation and sandboxing for media processing workflows
• Use containerization or process isolation for applications that must process untrusted media files
• Configure web applications to reject AVI file uploads until the vulnerability is patched

# Example: Disable GStreamer AVI plugin on Linux systems
# Move the AVI demuxer plugin to prevent loading
sudo mv /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstavi.so /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstavi.so.disabled

# Verify the plugin is no longer available
gst-inspect-1.0 avidemux