This vulnerability arises from a missing authorization check in the BrowserTag component of Google Chrome, allowing an attacker who has already compromised a renderer process to bypass the web origin policy. The flaw is identified as CWE-346 and CWE-863. Once exploited, the attacker can read or manipulate content from other origins that would normally be restricted, potentially leading to data theft or injection of malicious code across sites.

Google Chrome browsers running any version prior to 154.0.8037.57 are affected. No specific patch level below that is available, and users of later releases are not impacted by the authorization flaw.

The defect has a CVSS score of 6.3, indicating medium severity, with an EPSS score of 0.00235 and it is not listed in CISA’s KEV catalog. Exploitation requires the attacker to first gain control of the renderer process, which may occur through a local attack, malware, or compromised website content. Once the renderer is subverted, the attacker can serve a specially crafted HTML page that uses BrowserTag to circumvent origin separation, allowing operations across sites. The risk is heightened in environments where rendering processes are not tightly sandboxed or when extensions provide BrowserTag exposure.