CVE-2026-100763 in Firefox
Summary
by MITRE • 09/29/2026
Incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 157.
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Analysis
by VulDB Data Team • 09/29/2026
The identified security flaw resides within the WebGPU implementation of Mozilla Firefox, specifically concerning incorrect boundary condition handling during graphics processing operations. WebGPU is a modern web API designed to provide efficient access to GPU capabilities for rendering and compute tasks on the web platform. The vulnerability stems from an error in how memory boundaries are validated or enforced when executing shaders or managing buffer allocations within this component. Such errors typically involve off-by-one mistakes, integer overflows, or failures to properly check array indices against allocated memory sizes, leading to situations where the application accesses memory locations outside of their intended limits. This type of defect is a classic example of improper input validation and boundary checking, which are critical for maintaining memory safety in systems programming contexts that underlie browser graphics engines.
From a technical perspective, this flaw allows an attacker who can craft malicious web content utilizing WebGPU to trigger out-of-bounds reads or writes. An out-of-bounds read could potentially lead to the leakage of sensitive information stored in adjacent memory regions, such as credentials, session tokens, or other private data belonging to the user or other applications running on the same system. Conversely, an out-of-bounds write is significantly more dangerous, as it can corrupt heap metadata, overwrite function pointers, or alter critical variables within the browser process. This corruption creates a pathway for arbitrary code execution, allowing the attacker to run malicious scripts with the privileges of the user's current session. The severity of this vulnerability is heightened by its location in the graphics subsystem, which often operates with high-level access and may bypass certain sandboxing mechanisms if not properly isolated.
The operational impact of this vulnerability extends beyond simple data leakage or process crashes. If exploited successfully, it enables a remote code execution attack vector that does not require user interaction beyond visiting a malicious webpage containing the exploit payload. This aligns with common threat models where attackers embed exploits in compromised websites or phishing campaigns to gain initial access to a victim's machine. The presence of this flaw undermines the security guarantees provided by browser sandboxing, as successful exploitation could allow escape from the renderer process into more privileged contexts. Furthermore, because WebGPU is increasingly adopted for high-performance web applications including games and complex visualizations, the attack surface remains significant and growing. Users relying on Firefox for secure browsing are exposed to risks of data exfiltration or full system compromise if they encounter malicious content that leverages this specific boundary condition error in WebGPU operations.
To mitigate these risks, it is imperative to apply the security update included in Firefox version 157 immediately upon availability. This release contains patches that correct the boundary validation logic within the graphics engine, ensuring that memory accesses are strictly confined to allocated buffers and preventing unauthorized read or write operations. Organizations should enforce automatic updates for all endpoints running Firefox to ensure consistent protection against this vulnerability. Additionally, security teams can monitor network traffic for unusual patterns associated with WebGPU exploitation attempts, although such detection is challenging due to the encrypted nature of modern web communications. Implementing strict content security policies and restricting the use of experimental or high-privilege APIs in untrusted environments can further reduce exposure. Regular auditing of third-party libraries and dependencies that interact with browser graphics components also helps maintain a robust defense-in-depth posture against similar memory safety issues classified under CWE-125 for out-of-bounds reads or CWE-787 for out-of-bounds writes, which are commonly associated with such boundary condition flaws in ATT&CK techniques related to privilege escalation and data exfiltration.