CVE-2025-12445 is a policy bypass vulnerability affecting Google Chrome versions prior to 142.0.7444.59. The flaw resides in the browser's extension handling mechanism, where an attacker can craft a malicious Chrome extension that bypasses established policy controls designed to restrict extension capabilities. By exploiting this bypass, the malicious extension can leak cross-origin data, violating the same-origin policy that normally prevents such data exposure. This vulnerability is classified under CWE-288 (Authentication Bypass Using an Alternate Path or Channel), indicating that the extension can circumvent security controls without proper authentication or authorization. The attack vector requires that the attacker first convince a user to install the malicious extension, but no further user interaction is necessary. The CVSS v3.1 score is 6.5 (medium severity), reflecting the network attack vector, low attack complexity, no privileges required, no user interaction beyond installation, and impacts on confidentiality and integrity but not availability. No known exploits have been reported in the wild as of the publication date (November 10, 2025). The vulnerability highlights risks associated with extension management and the importance of enforcing strict policies on extension installation and permissions. Since Chrome is widely used globally, including across Europe, this vulnerability poses a significant risk to organizations that rely on Chrome for accessing sensitive web applications and data.

For European organizations, the primary impact of CVE-2025-12445 is the potential leakage of sensitive cross-origin data through malicious Chrome extensions. This can lead to unauthorized disclosure of confidential information, intellectual property, or personal data, potentially violating GDPR and other data protection regulations. The integrity of data accessed via Chrome extensions may also be compromised, undermining trust in web applications and internal systems. Since the vulnerability does not affect availability, denial-of-service impacts are unlikely. However, the ease of exploitation—requiring only user installation of a malicious extension—means that phishing or social engineering campaigns could be effective attack vectors. Organizations with employees who install extensions without strict controls are particularly at risk. The widespread use of Chrome in European enterprises, government agencies, and critical infrastructure sectors amplifies the potential impact. Data leakage incidents could result in regulatory fines, reputational damage, and operational disruptions. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits post-disclosure.

To mitigate CVE-2025-12445, European organizations should immediately update all Chrome installations to version 142.0.7444.59 or later, where the vulnerability is patched. Implement centralized management of Chrome extensions through enterprise policies that restrict installation to approved extensions only, preventing users from installing unvetted or malicious extensions. Employ browser security configurations that disable or limit extension capabilities, especially those that request cross-origin permissions. Conduct user awareness training focused on the risks of installing unauthorized browser extensions and recognizing social engineering attempts. Use endpoint protection solutions capable of detecting and blocking malicious extensions or unusual browser behaviors. Regularly audit installed extensions across organizational devices to identify and remove unauthorized ones. Monitor network traffic for unusual data exfiltration patterns that could indicate exploitation attempts. Finally, maintain an up-to-date inventory of browser versions and extension policies to ensure compliance with security standards.