CVE-2025-27091

Remediation/Mitigation Strategy: CVE-2025-27091 - OpenH264 Heap Overflow

This document outlines the remediation and mitigation strategy for CVE-2025-27091, a heap overflow vulnerability affecting OpenH264 codec library versions 2.5.0 and earlier.

1. Vulnerability Description:

  • Vulnerability Name: CVE-2025-27091 - OpenH264 Heap Overflow
  • Description: A race condition exists in the decoding functions of OpenH264 codec library versions 2.5.0 and earlier. This race condition occurs between a Sequence Parameter Set (SPS) memory allocation and a subsequent non-Instantaneous Decoder Refresh (non-IDR) Network Abstraction Layer (NAL) unit memory usage. A specially crafted video bitstream can exploit this vulnerability.
  • Affected Versions: OpenH264 versions 2.5.0 and earlier. Both Scalable Video Coding (SVC) mode and Advanced Video Coding (AVC) mode are affected.

2. Severity:

  • CVSS Score: 8.6 (High)
    • CVSS v3 Base Score: 8.6
    • CVSS v3 Vector: AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (Network, Low Attack Complexity, No Privileges Required, User Interaction, Unchanged Scope, High Confidentiality Impact, High Integrity Impact, High Availability Impact)
  • Severity Level: High
  • Rationale: Successful exploitation could allow an unauthenticated remote attacker to cause a crash in the victim’s decoding client and potentially execute arbitrary commands on the victim’s host through a heap overflow. The user interaction component requires the victim to process a malicious video, making exploitation reasonably likely.

3. Known Exploit:

  • Exploitability: There is a known method of exploitation by crafting a malicious H.264 bitstream. A victim processing this bitstream through a vulnerable version of OpenH264 can be compromised.
  • Impact: Exploitation leads to a heap overflow, potentially leading to:
    • Denial of Service (DoS): Application crash due to memory corruption.
    • Remote Code Execution (RCE): Arbitrary command execution on the victim’s host, granting the attacker full control of the system.

4. Remediation Strategy:

  • Primary Action: Upgrade OpenH264 to version 2.6.0 or later immediately. This is the most effective and recommended remediation. Versions 2.6.0 and later contain the fix for this vulnerability.
    • Identify affected systems: Locate all systems using OpenH264 versions 2.5.0 or earlier. This includes servers, desktops, embedded systems, and any application that uses OpenH264 for H.264 encoding/decoding.
    • Plan the upgrade: Develop a detailed upgrade plan, considering application dependencies and potential downtime. Test the upgraded version in a non-production environment before deploying to production.
    • Execute the upgrade: Follow the official upgrade instructions provided with OpenH264. Verify the upgrade’s success by confirming the OpenH264 version.

5. Mitigation Strategy (If immediate upgrade is not possible):

  • Note: Mitigation measures offer limited protection and should only be used as a temporary solution until a full upgrade can be performed.

  • Input Validation and Sanitization: While not a direct fix for the heap overflow, robust input validation and sanitization of H.264 bitstreams can reduce the likelihood of malicious data triggering the vulnerability. This includes:

    • Strict H.264 conformance checks: Implement rigorous checks to ensure that incoming bitstreams adhere to H.264 standards. Reject malformed or non-conforming streams.
    • Bitstream size limits: Enforce limits on the size of H.264 bitstreams processed. Unusually large bitstreams may indicate malicious intent.
    • NAL unit validation: Validate the structure and contents of Network Abstraction Layer (NAL) units within the H.264 bitstream. Look for unexpected or suspicious patterns.

  • Sandboxing/Isolation: Run applications that use OpenH264 in a sandboxed or isolated environment. This limits the potential impact of a successful exploit by restricting the attacker’s access to the underlying system. Consider using technologies like:

    • Virtualization: Run OpenH264-dependent applications within virtual machines.
    • Containerization: Utilize Docker or other containerization technologies to isolate OpenH264 processes.
    • Operating System-Level Sandboxing: Employ OS-level sandboxing mechanisms (e.g., AppArmor, SELinux) to restrict application privileges.

  • Network Segmentation: Segment the network to isolate systems running vulnerable versions of OpenH264. This limits the potential spread of an attacker if one system is compromised.

  • Monitor for Suspicious Activity: Implement monitoring and alerting mechanisms to detect suspicious activity related to H.264 processing. Look for:

    • Unexpected application crashes: Frequent crashes in applications using OpenH264 may indicate an exploit attempt.
    • High CPU or memory usage: Unusual resource consumption during H.264 decoding could be a sign of malicious activity.
    • Network traffic anomalies: Look for suspicious network connections or data transfers originating from systems processing H.264 streams.

6. Post-Remediation Actions:

  • Verify the upgrade: Confirm that all affected systems have been successfully upgraded to OpenH264 version 2.6.0 or later.
  • Perform vulnerability scanning: Conduct regular vulnerability scans to identify any remaining instances of vulnerable software and ensure that new vulnerabilities are quickly detected.
  • Monitor logs and alerts: Continuously monitor system logs and security alerts for any signs of suspicious activity.

7. Communication:

  • Inform all relevant stakeholders (system administrators, developers, users) about the vulnerability and the remediation steps being taken.
  • Provide clear instructions for users on how to report any suspicious activity.

Disclaimer: This remediation strategy is based on the available information at the time of writing. It is essential to consult the official OpenH264 documentation and security advisories for the most up-to-date information and guidance. Always test thoroughly before deploying any changes to a production environment.

Assigner

Date

  • Published Date: 2025-02-20 18:15:27
  • Updated Date: 2025-02-27 20:18:13

More Details

CVE-2025-27091