CVE-2025-27091 is a high-severity vulnerability affecting the Cisco OpenH264 codec library, which is widely used for H.264 video encoding and decoding. This vulnerability allows a remote, unauthenticated attacker to exploit a heap overflow due to a race condition in the decoding functions. Specifically, the issue arises from the improper handling of memory allocation for Sequence Parameter Sets (SPS) and the subsequent processing of non-Instantaneous Decoder Refresh (non-IDR) Network Abstraction Layer (NAL) units.
With a CVSS score of 8.6, this vulnerability is classified as high severity, indicating significant risk to organizations that utilize OpenH264 versions 2.5.0 and earlier. Attackers may leverage this vulnerability by crafting a malicious bitstream and tricking victims into processing a video containing the exploit. The consequences may include unexpected crashes in the decoding client and potentially arbitrary command execution on the victim's system.
Organizations utilizing affected versions of OpenH264 must prioritize patching immediately, as OpenH264 versions 2.6.0 and later contain the necessary fix for this vulnerability. There are currently no known workarounds, making the upgrade crucial to prevent potential exploitation.
The urgency for defenders cannot be overstated, as the implications of this vulnerability extend beyond mere application failure; they could lead to severe security breaches if exploited. Organizations are advised to assess their use of OpenH264 and plan for immediate updates.
Vulnerability Details
The OpenH264 vulnerability, officially described in CVE-2025-27091, pertains to a heap overflow in the codec library's decoding functions that results from a race condition. The vulnerability affects versions 2.5.0 and earlier and is addressed in version 2.6.0 and later. The Common Weakness Enumeration (CWE) classifications for this vulnerability include CWE-122 and CWE-787, indicating issues related to improper bounds checking and out-of-bounds write, respectively.
The CVSS score of 8.6 reflects a high level of risk, with the vulnerability being exploitable remotely via a network. Attack complexity is considered low, requiring only that the victim user process a maliciously crafted video. The impacts on confidentiality, integrity, and availability are all rated high, reinforcing the need for prompt action.
Technical Analysis
The root cause of CVE-2025-27091 lies in the race condition between memory allocation and usage within the OpenH264 codec. An attacker can exploit this condition by sending a specially crafted bitstream to a victim, potentially leading to a heap overflow. This type of vulnerability allows the attacker to manipulate the memory of the affected application, leading to unpredictable behavior, including crashes and arbitrary code execution.
The attack vector is network-based, requiring no privileges from the attacker, but necessitating user interaction to process the malicious video. The complexity of the attack is low, making it a feasible threat for exploitation. The potential for confidentiality, integrity, and availability impacts underscores the critical nature of this vulnerability.
Risk & Impact Analysis
The real-world risk of CVE-2025-27091 is substantial. Organizations using OpenH264 in any capacity, especially in environments where video processing occurs, are at risk. The potential for arbitrary command execution could lead to significant breaches, including unauthorized access to sensitive data or the compromise of entire systems.
Given the high CVSS score and the exploitability of this vulnerability, organizations should treat it as a high priority. The blast radius for potential exploitation extends to any system processing affected versions of OpenH264, increasing the urgency for organizations to address this vulnerability in their patch cycles.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects OpenH264 version 2.5.0 and earlier. Users are strongly advised to upgrade to version 2.6.0 or later to mitigate any risks associated with this vulnerability. The absence of known workarounds emphasizes the necessity of this update.
Mitigation & Remediation
To mitigate the risks associated with CVE-2025-27091, organizations must patch their OpenH264 installations by upgrading to version 2.6.0 or later. This version contains the fix for the heap overflow vulnerability. Since there are no known workarounds, immediate action is required to secure systems against potential exploitation.
Organizations should also consider implementing security controls such as monitoring for abnormal application behavior and restricting access to affected systems until the upgrade is completed. For further information on security practices, organizations can refer to comprehensive resources on continuous penetration testing and other security assessments.
Detection Guidance
To detect potential exploitation of CVE-2025-27091, organizations should monitor logs for indicators of abnormal decoding behavior and unauthorized access attempts. Behavioral anomalies in the decoding client may indicate attempts to exploit the heap overflow vulnerability. Additionally, network signatures associated with malicious video streams should be analyzed to prevent exploitation.
AppSecure Threat Intelligence Insight
CVE-2025-27091 represents a critical risk for organizations relying on OpenH264 for video processing. The vulnerability's nature reflects a broader trend in software vulnerabilities where race conditions can lead to severe exploitation opportunities. Security teams should take this incident as a lesson to regularly review and update their software components, ensuring they are protected against similar vulnerabilities.
Organizations may benefit from developing a robust vulnerability management program to address potential risks proactively. Emphasizing continuous security practices will help organizations stay ahead of vulnerabilities like CVE-2025-27091.
Moreover, utilizing effective penetration testing methodologies can provide deeper insights into the security posture and help identify vulnerabilities before they can be exploited.
In conclusion, CVE-2025-27091 serves as a reminder of the importance of timely software updates and comprehensive security assessments to mitigate potential risks and protect organizational assets.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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