In a proactive cybersecurity measure, Google has issued an urgent update for its Chrome browser to patch four vulnerabilities, including a high-severity flaw that has already been exploited in the wild. The vulnerability, tracked as CVE-2025-4664, involves insufficient policy enforcement in Chrome’s Loader component and could allow remote attackers to exfiltrate sensitive user data through manipulated HTML pages. Security researcher Vsevolod Kokorin uncovered the issue, demonstrating how referrer-policy manipulation can lead to full account compromise. Chrome users across Windows, Mac, and Linux platforms are strongly urged to update to the latest versions, as are users of Chromium-based browsers.
Understanding the Vulnerability: CVE-2025-4664
At the core of this security update is CVE-2025-4664, a high-severity bug rated with a CVSS score of 4.3. The flaw arises from inadequate enforcement of security policies within Chrome’s Loader component, which processes resource links embedded in web pages.
The exploit leverages Chrome's handling of the Link HTTP header in sub-resource requests. Unlike other browsers, Chrome permits the Link header to modify the referrer-policy, allowing attackers to set it to unsafe-url. This exposes the full URL—including sensitive query parameters—when a crafted HTML page is loaded.
According to security researcher Vsevolod Kokorin, who responsibly disclosed the vulnerability on May 5, 2025, these query parameters could include authentication tokens or other confidential information. In a proof-of-concept (PoC) shared via social media, Kokorin illustrated how these details could be exfiltrated using embedded third-party images, posing a significant risk of account takeover.
Confirmed Exploitation and Security Implications
What elevates the urgency of this issue is the confirmation that CVE-2025-4664 has been actively exploited in the wild. While Google has not disclosed specific instances or the scale of exploitation, the public availability of a PoC raises red flags for enterprise and individual users alike.
This marks the second zero-day vulnerability under active exploitation in Chrome this year, following CVE-2025-2783. Such vulnerabilities are of particular concern as they can be weaponized quickly, often before users apply available patches.
The flaw’s exploitation method—harvesting sensitive data through query strings—highlights the growing sophistication of browser-based attacks, particularly those that sidestep traditional defenses by abusing standard browser functionality.
Recommended Updates and Precautionary Measures
To mitigate risk, Google has released patched versions of Chrome:
- Windows and macOS: 136.0.7103.113/.114
- Linux: 136.0.7103.113
Users should ensure their browsers are updated immediately. The Chrome update is delivered automatically but can be manually initiated via Settings > About Chrome.
Importantly, this vulnerability affects not just Chrome, but all browsers built on the Chromium engine, including Microsoft Edge, Brave, Opera, and Vivaldi. Users of these platforms should remain vigilant and apply security updates as soon as vendors release them.
Broader Cybersecurity Context
The increasing frequency of high-profile browser vulnerabilities underscores the complex nature of modern web security. As browser capabilities expand to support new web standards and performance optimizations, so too do the attack surfaces they present.
Enterprises and developers must adopt a layered approach to cybersecurity. This includes enabling strict Content Security Policies (CSP), sanitizing URLs and query strings, and minimizing the exposure of sensitive data in client-side components.
At the user level, routine browser updates, cautious link interaction, and the use of reputable password managers remain essential pillars of online safety.
Conclusion
Google’s swift response to CVE-2025-4664 is commendable, but the broader lesson remains clear: even widely used platforms with robust security postures are not immune to emerging threats. As browser-based attacks become increasingly nuanced, maintaining cybersecurity hygiene—both at the individual and organizational level—is no longer optional. Timely updates, informed usage, and proactive security monitoring are critical to staying ahead of potential breaches in an interconnected digital environment.
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