CVE-2025-6663: GStreamer H266 Codec Parsing Vulnerability Leads to Remote Code Execution
A stack-based buffer overflow vulnerability has been discovered in the H266 codec parsing functionality of GStreamer. This flaw, identified as CVE-2025-6663, could allow a remote attacker to execute arbitrary code on a system running a vulnerable version of GStreamer.
Vulnerability Details
- CVE ID: CVE-2025-6663
- Description: The vulnerability lies in the parsing of H266 SEI (Supplemental Enhancement Information) messages within GStreamer. Specifically, the code fails to properly validate the length of user-supplied data before copying it into a fixed-size, stack-based buffer. This can lead to a buffer overflow.
- CVSS Score and Vector:
- CVSS v3.0 Score: 7.8 (High)
- CVSS v3.0 Vector: AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Explanation: This vulnerability has a CVSS score of 7.8, which is considered High. The attack vector is Local (AV:L), meaning an attacker needs local access to the system. The attack complexity is Low (AC:L), implying that the attack is relatively easy to execute. No privileges are required (PR:N), but user interaction is required (UI:R), meaning a user needs to perform some action (e.g., open a malicious file) to trigger the exploit. The scope is Unchanged (S:U), meaning the vulnerability impacts the same privilege level. Successful exploitation can lead to High Confidentiality (C:H), High Integrity (I:H), and High Availability (A:H) impact, meaning the attacker could steal sensitive data, modify system files, and cause a denial-of-service condition.
- Exploit Requirements: User interaction is required, making social engineering a possible attack vector. An attacker needs to entice a user to interact with specially crafted media content that triggers the vulnerable code path.
- Affected Vendor, Product, Version: GStreamer. Specific versions are awaiting further analysis.
- CWE: CWE-121 (Stack-based Buffer Overflow) - This occurs when a program writes beyond the boundaries of a buffer allocated on the stack. This can lead to crashes, arbitrary code execution, or other unintended behaviors.
Timeline of Events
- 2025-07-07: CVE ID Assigned and initial report published.
- 2025-07-08: Report updated with additional details.
Exploitability & Real-World Risk
The real-world risk is considerable. While user interaction is required, GStreamer is a widely used multimedia framework integrated into many applications. Attackers could embed malicious H266 streams in seemingly harmless files or websites, potentially affecting a large number of users. Successful exploitation allows the attacker to execute arbitrary code within the context of the application using GStreamer. This could allow for complete system compromise depending on the application’s privileges.
Recommendations
- Apply the latest patches for GStreamer.
- Avoid opening media files from untrusted sources.
- Monitor systems for suspicious activity, especially related to media processing.
- Implement robust input validation to prevent buffer overflows.
Technical Insight
The vulnerability is caused by insufficient bounds checking when parsing H266 SEI messages. The code copies data from the input stream into a fixed-size buffer on the stack without verifying that the input data's length does not exceed the buffer's capacity. This allows an attacker to overwrite adjacent memory locations on the stack, including return addresses, enabling arbitrary code execution.
Credit to Researcher(s)
This vulnerability was discovered by the Zero Day Initiative.
References
Tags
#GStreamer #CVE-2025-6663 #H266 #Codec #RCE #RemoteCodeExecution #BufferOverflow #Security #Vulnerability
Summary: A stack-based buffer overflow vulnerability (CVE-2025-6663) exists in GStreamer's H266 codec parsing, allowing remote attackers to execute arbitrary code via crafted media content. User interaction is required, making social engineering a viable attack vector. Apply patches and avoid untrusted media sources.
CVE ID: CVE-2025-6663
Risk Analysis: Successful exploitation allows an attacker to execute arbitrary code with the privileges of the process running GStreamer. This could lead to sensitive data theft, system compromise, or denial of service.
Recommendation: Apply the latest patches for GStreamer. Exercise caution when opening media files from untrusted sources. Implement robust input validation to prevent buffer overflows.
Timeline
- 2025-07-07: CVE ID Assigned and initial report published
- 2025-07-08: Report updated with additional details