CVE-2026-117996 in Firefox
Summary
by MITRE • 10/27/2026
Incorrect boundary conditions in the WebRTC component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.
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Analysis
by VulDB Data Team • 10/27/2026
The identified security issue resides within the WebRTC implementation of Mozilla Firefox, specifically concerning incorrect boundary condition handling during data processing operations. WebRTC is a foundational technology for real-time communication, enabling peer-to-peer audio, video, and generic data exchange directly between browsers without requiring intermediate servers. The vulnerability arises from improper validation or manipulation of memory boundaries when parsing or constructing specific media streams or signaling messages. In software engineering terms, this typically manifests as an out-of-bounds read or write error where the application fails to correctly verify that a requested index or length falls within the allocated limits of a buffer. Such flaws are critical because they allow for potential unauthorized access to memory contents or corruption of adjacent data structures, which can destabilize the browser process and create avenues for further exploitation.
From a technical perspective, this flaw aligns with Common Weakness Enumeration categories such as CWE-125 Out-of-bounds Read or CWE-787 Out-of-bounds Write, depending on whether the boundary violation results in information leakage or memory corruption. The presence of incorrect boundary conditions suggests that the input validation logic did not adequately account for edge cases where data lengths exceed expected parameters or when negative indices are processed incorrectly. In the context of WebRTC, this could involve malformed RTP packets, SCTP messages, or SDP offers and answers that trigger these faulty checks during decoding or encoding processes. The severity is heightened by the fact that WebRTC components often run with elevated privileges relative to standard web content due to their direct access to hardware resources like cameras and microphones, making any memory safety issue particularly dangerous for user privacy and system integrity.
The operational impact of this vulnerability allows a remote attacker who can trick a victim into visiting a malicious webpage or interacting with a compromised WebRTC application to potentially execute arbitrary code via the browser process. If exploited successfully through an out-of-bounds write, it could lead to heap corruption, enabling control over program execution flow and resulting in full system compromise under certain conditions. Even if limited to an out-of-bounds read, sensitive information such as keystrokes, screen contents, or other memory data residing near the affected buffer could be exfiltrated by the attacker. This represents a significant risk to confidentiality and integrity, particularly for users who rely on Firefox for secure communications in professional or personal contexts where privacy is paramount.
Mozilla addressed this vulnerability in Firefox 159 and Firefox Extended Support Release (ESR) version 153.6 through rigorous code review and the implementation of stricter bounds checking mechanisms within the WebRTC stack. The fix likely involved adding explicit length validations before memory access operations, ensuring that all indices are verified against allocated buffer sizes prior to dereferencing pointers. Users are strongly advised to update their browsers immediately to mitigate this risk. For organizations deploying Firefox ESR, it is essential to verify that patch management systems have successfully applied version 153.6 or later across all endpoints. Additionally, security teams should monitor for any indicators of compromise related to WebRTC activity and consider implementing network-level controls such as Content Security Policy headers to restrict unauthorized media stream initiation where feasible. Regular updates remain the primary defense against such memory safety vulnerabilities in complex web technologies.