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November 15, 2023
Executive Summary
The Cisco OpenH264 vulnerability, identified as CVE-2025-27091, presents a critical security issue within the Cisco OpenH264 codec library, affecting versions up to 2.5.x. This vulnerability is characterized by a heap-based buffer overflow resulting from a race condition, which could potentially allow unauthenticated attackers to execute arbitrary commands. Although there are no known instances of this vulnerability being exploited in the wild, it is essential for users to upgrade to the latest version to mitigate any potential risks.
Technical Information
The Cisco OpenH264 codec library is widely used for video encoding and decoding tasks, supporting both Scalable Video Coding (SVC) and Advanced Video Coding (AVC) modes. The identified vulnerability, CVE-2025-27091, is a result of a race condition that leads to a heap-based buffer overflow. This flaw arises when concurrent video processing tasks access shared resources without proper synchronization, leading to memory corruption. Attackers can exploit this condition by delivering a specially crafted video bitstream to the vulnerable system, triggering the buffer overflow and potentially allowing the execution of arbitrary code.
This vulnerability affects Cisco OpenH264 versions 2.5.0 and earlier. The vulnerability's exploitation is contingent upon the processing of a malicious video bitstream, which can be delivered through various attack vectors such as email attachments, malicious web pages, or compromised video streaming services. Once the bitstream is processed, the race condition can be triggered, leading to memory corruption and the possibility of remote code execution.
The discovery of this vulnerability underscores the critical importance of secure coding practices in the development of multimedia processing libraries. The use of concurrent processing in video codecs, while enhancing performance, introduces complexity that can lead to security vulnerabilities if not properly managed. As such, developers must employ robust synchronization mechanisms to prevent race conditions and ensure the integrity of memory operations.
Exploitation in the Wild
To date, there have been no confirmed reports of CVE-2025-27091 being exploited in the wild. However, the potential for exploitation exists, particularly given the widespread use of the Cisco OpenH264 codec in various applications and systems. Security researchers and network administrators are advised to remain vigilant and monitor for any signs of exploitation, such as unusual traffic patterns or unexpected process behavior associated with video decoding activities.
APT Groups using this vulnerability
Currently, there are no known Advanced Persistent Threat (APT) groups or other threat actors identified by MITRE or other sources as actively exploiting this specific vulnerability. However, the absence of known exploitation does not diminish the need for proactive mitigation measures to prevent potential attacks.
Affected Product Versions
The products affected by CVE-2025-27091 include Cisco OpenH264 codec library versions 2.5.0 and earlier. Both the SVC and AVC modes are impacted by this vulnerability. It is imperative for organizations utilizing these versions to expedite the upgrade process to the latest patched release.
Workaround and Mitigation
The primary mitigation strategy for CVE-2025-27091 is to upgrade affected systems to Cisco OpenH264 version 2.6.0 or later, where the vulnerability has been resolved. Additionally, organizations should implement comprehensive network monitoring solutions to detect any anomalous activities related to video decoding processes. Regular security audits and code reviews are recommended to identify and remediate potential vulnerabilities in multimedia processing software.
References
For further details on CVE-2025-27091, please refer to the following resources: The National Vulnerability Database (NVD) entry at https://nvd.nist.gov/vuln/detail/CVE-2025-27091 provides technical details and severity ratings. The GitHub Security Advisory at https://github.com/cisco/openh264/security/advisories/GHSA-m99q-5j7x-7m9x offers insights into the vulnerability's impact and recommended actions. Cisco's OpenH264 Release Notes at https://github.com/cisco/openh264/releases/tag/v2.6.0 outline the changes and fixes implemented in the latest version.
Rescana is here for you
At Rescana, we are dedicated to helping our clients navigate the complexities of cybersecurity risk management. Our Third Party Risk Management (TPRM) platform is designed to provide comprehensive insights into the security posture of your vendors and partners, enabling you to identify and mitigate potential risks before they impact your organization. If you have any questions about this report or other cybersecurity concerns, please reach out to us at ops@rescana.com. We are here to support you in safeguarding your digital assets.