GStreamer H.266 Codec Exploit Unveiled: Analyzing CVE-2025-6663's Stack-Based Buffer Overflow

Introduction

Imagine opening a seemingly harmless video file, only to find your system compromised by a hidden threat. This scenario is precisely what CVE-2025-6663, a stack-based buffer overflow vulnerability in GStreamer's H.266 codec parser, could enable. GStreamer is a widely-adopted multimedia framework integral to Linux distributions, video conferencing tools, and embedded systems. The vulnerability affects versions 1.26.0 through 1.26.2, posing a significant risk of remote code execution.

Technical Information

The flaw specifically exists within the gst-plugins-bad module, during the parsing of Supplemental Enhancement Information (SEI) messages in H.266 video streams. The parser neglects to validate the length of user-supplied data before copying it into a fixed-length stack buffer. This oversight leads to a buffer overflow, allowing attackers to overwrite critical memory structures such as return addresses and frame pointers. By crafting malicious H.266 files, attackers can exploit this vulnerability to execute arbitrary code in the context of the affected application, potentially leading to full system compromise.

Attack vectors primarily involve user interaction, such as opening maliciously crafted video files delivered via email attachments, websites, or streaming services. The vulnerability does not require authentication, significantly lowering the barrier for exploitation.

Patch Information

To address the stack buffer overflow vulnerability in the H.266 video bitstream parser, the GStreamer team has released version 1.26.3 of the gst-plugins-bad module. This update includes a critical fix that prevents potential crashes and mitigates the risk of code execution through stack manipulation.

The patch specifically corrects the buffer overflow issue by implementing proper bounds checking during the parsing process. This ensures that the parser does not read or write beyond the allocated memory, thereby maintaining the integrity and stability of the application.

For users operating on versions of GStreamer between 1.26.0 and 1.26.2, it is strongly recommended to upgrade to version 1.26.3. This can be accomplished by downloading the latest release from the GStreamer official website and following the standard upgrade procedures. Alternatively, for those who prefer to apply the patch manually, the GStreamer project provides a detailed patch file that can be applied to the existing source code, followed by recompilation.

By updating to the patched version, users can safeguard their systems against potential exploits that leverage this vulnerability. Maintaining up-to-date software is a fundamental practice in ensuring the security and reliability of multimedia applications.

Detection Methods

Detecting vulnerabilities like the stack buffer overflow in the H.266 video parser requires a multifaceted approach. Security tools such as Tenable's Nessus utilize plugins to identify specific vulnerabilities. These plugins operate by scanning systems for known issues, leveraging attributes like CVE identifiers to pinpoint vulnerabilities. For instance, Tenable's plugin attributes include fields such as 'cve', 'description', and 'solution', which help in identifying and understanding vulnerabilities.

In the case of the H.266 video parser vulnerability, a dedicated plugin would scan for the specific CVE associated with this issue. By referencing the CVE identifier, the plugin can detect if the vulnerable version of the GStreamer plugin is present on the system. This method ensures that the detection process is both accurate and efficient, allowing for timely remediation.

It's important to note that while these plugins are effective, they rely on up-to-date vulnerability databases and regular scans to maintain security. Therefore, keeping security tools updated and conducting frequent system scans are essential practices in identifying and mitigating such vulnerabilities.

Affected Systems and Versions

The vulnerability specifically affects GStreamer versions 1.26.0 through 1.26.2, including the gst-plugins-bad module. Systems processing H.266 video content using these versions are vulnerable and should be updated immediately to version 1.26.3.

Vendor Security History

GStreamer has previously encountered similar vulnerabilities in codec parsers, indicating recurring memory safety issues. Historically, the vendor has demonstrated a proactive security posture, typically releasing patches within a 30-day remediation window for critical vulnerabilities. The swift response to CVE-2025-6663, with a patch released within 24 days of disclosure, underscores GStreamer's commitment to security.

References

Source: This report was created using AI

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A critical stack-based buffer overflow in GStreamer's H.266 codec parser (CVE-2025-6663) could lead to remote code execution. Here's what you need to know.

CVE Analysis