CVE-2026-93378 is a vulnerability in Google Chrome's Storage subsystem that allows an attacker with control over the renderer process to bypass site isolation protections by leveraging a specially crafted PDF file. This issue affects Chrome versions before 153.0.8010.52. Site isolation is a security feature designed to separate different websites into different processes to prevent data leakage and cross-site attacks. The vulnerability could enable an attacker to circumvent these protections, potentially increasing the risk of data exposure or privilege escalation within the browser context.

The vulnerability enables bypass of site isolation, which could allow an attacker who has already compromised the renderer process to access or interfere with data from other sites that should be isolated. This increases the risk of cross-site data leakage or unauthorized access within the browser environment. However, exploitation requires prior compromise of the renderer process and delivery of a crafted PDF file.

Google has released an update to address this vulnerability in Chrome version 153.0.8010.52. Users and administrators should update to this version or later to remediate the issue. No additional mitigation steps are indicated by the vendor advisory.