CVE-2026-117905 in Firefox
Summary
by MITRE • 10/27/2026
Use-after-free in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6.
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Analysis
by VulDB Data Team • 10/28/2026
The identified vulnerability represents a critical memory management error classified as an out-of-bounds write resulting from use-after-free conditions within the Audio/Video playback subsystem of Mozilla Firefox. This specific class of flaws occurs when software continues to utilize a pointer after the memory it references has been deallocated or freed, leading to undefined behavior that can be exploited by malicious actors. In the context of browser-based media processing, such vulnerabilities are particularly dangerous because they reside in components responsible for handling complex binary data streams and dynamic resource allocation during playback operations. The flaw allows an attacker who successfully exploits this condition to execute arbitrary code with the privileges of the target process, effectively compromising the integrity and confidentiality of the user's system through a remote attack vector delivered via malicious web content.
From a technical perspective, use-after-free vulnerabilities in multimedia engines often stem from race conditions or improper lifecycle management of media decoder objects. When an audio or video stream is processed, various buffers and object instances are allocated to handle decoding, rendering, and synchronization tasks. If the application fails to properly nullify pointers after freeing these resources, or if it accesses them during a window where they have been reallocated for different purposes, an attacker can manipulate memory contents to achieve code execution. This specific instance highlights the complexity of managing asynchronous operations in high-performance media pipelines, where timing discrepancies between garbage collection mechanisms and active playback threads can leave dangling references accessible to external inputs crafted through specially designed HTML or JavaScript payloads embedded in a webpage.
The operational impact of this vulnerability is severe, as it enables remote code execution without requiring user interaction beyond visiting the malicious site if appropriate security mitigations are bypassed. Attackers could leverage this flaw to install malware, steal sensitive information such as cookies and session tokens, or establish persistent access to the victim's machine. The risk is amplified by the ubiquity of web-based media consumption, meaning that users browsing normal websites containing embedded video players or audio streams could inadvertently trigger the exploit if the page contains maliciously crafted code designed to interact with the vulnerable playback component. This underscores the importance of timely patching and the inherent risks associated with running complex software stacks within a sandboxed browser environment where isolation boundaries must be strictly maintained against sophisticated memory corruption attacks.
To mitigate this risk, organizations and individual users should ensure that Mozilla Firefox is updated immediately to version 159 or later for standard releases, or versions 115.44 and 153.6 for Extended Support Release channels. These updates contain the necessary code corrections to properly manage memory lifecycles within the media playback engine, preventing access to freed memory regions. Additionally, security teams should enforce strict content security policies and consider deploying browser isolation technologies or advanced endpoint detection systems that can identify anomalous behavior patterns associated with memory corruption exploits. Regular vulnerability scanning and patch management cycles are essential to maintain a strong defense posture against such high-severity flaws in widely used web browsers.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-416, which describes use-after-free conditions as a significant category of software errors leading to security breaches. In the context of the MITRE ATT&CK framework, exploitation techniques related to this flaw fall under Tactic 12: Defense Evasion and Technique T1059 Command and Scripting Interpreter if used for initial access or lateral movement, though more accurately it relates to memory corruption exploits often categorized under execution vectors like T1203 Exploitation for Client Execution. Understanding these mappings helps security professionals prioritize remediation efforts based on the potential impact of similar vulnerabilities across their infrastructure.