CVE-2026-92045 in Firefox
Summary
by MITRE • 09/15/2026
Sandbox escape due to incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 156 and Firefox ESR 153.3.
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Analysis
by VulDB Data Team • 09/15/2026
The identified security flaw resides within the WebRTC implementation of Mozilla Firefox, specifically involving a failure in enforcing correct boundary conditions during data processing operations. WebRTC is a critical framework for real-time communication that handles complex streams of audio, video, and generic data between browsers or applications. When handling these media streams, the underlying engine must strictly validate input parameters to ensure they fall within expected memory limits and structural constraints. In this instance, the boundary checks were insufficient or incorrectly implemented, allowing an attacker to supply crafted inputs that exceed the intended operational boundaries of the component. This type of error typically leads to out-of-bounds reads or writes, which are among the most dangerous classes of vulnerabilities in modern software engineering because they can corrupt memory structures and lead to arbitrary code execution.
From a technical perspective, this vulnerability aligns with CWE-125, Out-of-Bounds Read, or potentially CWE-787, Out-of-Bounds Write, depending on whether the malformed input causes the application to read beyond allocated buffers or write data into unintended memory locations. The lack of proper boundary validation means that when a malicious actor triggers this code path through a specially crafted WebRTC session description or media packet, they can manipulate the program counter or overwrite adjacent memory regions. This manipulation allows for potential sandbox escape scenarios where the attacker breaks out of the browser's security container to execute arbitrary commands on the host operating system with the privileges of the user running the browser. Such exploits are particularly dangerous because they bypass standard web isolation mechanisms that protect users from malicious websites and scripts.
The operational impact of this vulnerability is severe, as it enables remote code execution without requiring any physical access or prior authentication beyond a victim visiting a compromised webpage or interacting with a malicious WebRTC connection. An attacker could leverage this flaw to install malware, steal sensitive data such as credentials or session cookies, or use the infected machine as part of a botnet. The severity is further amplified by the widespread adoption of WebRTC for legitimate business and personal communications, meaning that many users may have active connections open without realizing they are processing untrusted media streams from potentially hostile sources. This vulnerability affects both standard releases of Firefox version 156 and the Extended Support Release (ESR) version 153.3, indicating a systemic issue in the core rendering engine rather than an isolated edge case.
In terms of threat modeling, this exploit technique corresponds to MITRE ATT&CK techniques related to initial access via browser exploitation and subsequent privilege escalation or lateral movement through sandbox escape. Attackers often use such vulnerabilities as part of drive-by download campaigns where a single visit to a malicious site triggers the chain of events leading to full system compromise. The ability to escape the browser sandbox effectively neutralizes many defense-in-depth strategies that rely on process isolation, making this a high-priority issue for security teams and end-users alike.
To mitigate the risks associated with this vulnerability, it is imperative that all users upgrade their Firefox installations immediately to version 156 or later if using standard releases, or version 153.3 or later for ESR channels. These updates contain patches that enforce stricter boundary checks within the WebRTC component, ensuring that input data is validated against expected limits before processing occurs. Organizations should also consider implementing network-level controls such as Content Security Policy (CSP) headers to restrict which origins can initiate WebRTC connections and deploying endpoint detection and response solutions capable of identifying anomalous memory access patterns indicative of exploitation attempts. Regular patch management cycles are essential to address such critical flaws promptly, minimizing the window of exposure during which attackers could develop and deploy functional exploits against unpatched systems.