CVE-2026-16393 is a security vulnerability in Mozilla Firefox's Graphics: WebGPU component caused by incorrect boundary conditions, classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). This vulnerability allows remote attackers to potentially cause significant impact on confidentiality and availability without requiring user interaction. The issue was resolved in Firefox 153 and Thunderbird 153. The Mozilla advisory lists this vulnerability among multiple high-impact security fixes released on July 21, 2026. The vulnerability affects all Firefox versions prior to 153.

The vulnerability allows remote attackers to exploit incorrect boundary conditions in the WebGPU graphics component, potentially leading to high confidentiality and availability impacts. According to the CVSS vector, the attack requires no privileges and no user interaction, making it highly exploitable. However, no known exploits in the wild have been reported at this time.

Mozilla has released an official fix for this vulnerability in Firefox version 153. Users and administrators should update affected Firefox installations to version 153 or later to remediate this issue. Since this is not a cloud service, patching the client software is required. There are no vendor advisories indicating that no action is required or that the issue is already mitigated without patching.