Advisory on Zero-Day Vulnerability in Google Chrome

Overview

Google has released an emergency security update to address a high-severity zero-day vulnerability (CVE-2025-10585) in its Chrome web browser. This vulnerability, which is being actively exploited, is related to a Type Confusion flaw in the V8 JavaScript and WebAssembly engine. The update, which is rolling out now, affects Chrome versions prior to 140.0.7339.185 and addresses multiple vulnerabilities, including the zero-day. Users are strongly advised to update their browsers immediately to protect against potential attacks.

Vulnerability Details

The flaw, CVE-2025-10585, occurs in the V8 engine, allowing attackers to exploit type confusion, leading to memory corruption and potentially arbitrary code execution. This could allow a remote attacker to escape Chrome’s security sandbox by tricking a user into visiting a specially crafted webpage. This issue was discovered by Google’s Threat Analysis Group (TAG) on September 16, 2025, and is actively being exploited in the wild.

In addition to this zero-day, the update also addresses three other vulnerabilities, including:

CVE-2025-10500	A use-after-free vulnerability in Dawn, a graphics abstraction layer.
CVE-2025-10501	A use-after-free flaw in WebRTC, which enables real-time communication.
CVE-2025-10502	A heap buffer overflow in ANGLE, a graphics engine translation layer.

How It Affects

The active exploitation of the zero-day vulnerability means that unpatched systems are at significant risk of compromise. Attackers could leverage this flaw to execute arbitrary code, potentially leading to a full system compromise.

Other vulnerabilities patched in this update can also lead to memory corruption and code execution. These flaws, while not yet actively exploited, could also pose serious risks to users who delay the update.

Potential Risks

Security: Exploitation of the vulnerability could result in arbitrary code execution and system compromise.
Privacy: Attackers could gain access to sensitive data if they manage to bypass Chrome's sandbox.
Compliance: Unpatched systems might lead to non-compliance with security standards, especially in industries that require regular patching.

Who It Affects

All Google Chrome users across Windows, macOS, and Linux platforms are impacted by this vulnerability. Given the nature of the zero-day, it is critical for all users to update their browsers as soon as possible. The issue is particularly relevant for organizations with large-scale deployments of Chrome, as the risk of exploitation increases with wider usage.

Impact

Security: The vulnerability poses a significant risk to users and organizations by allowing attackers to execute arbitrary code remotely.
Compliance: Organizations may face compliance issues if the flaw is exploited and they fail to patch their systems promptly.
Forensics: Post-incident investigations could be hindered if the vulnerability is exploited and not addressed in time.

Targeted Products

Google Chrome across:
- Windows
- macOS
- Linux

Recommendations

Update Chrome
- Ensure that all systems are updated to Chrome version 140.0.7339.185/.186 (Windows/Mac) or 140.0.7339.185 (Linux).
- Users can check their current Chrome version by navigating to the “Help” menu and selecting “About Google Chrome.” Ensure automatic updates are enabled to receive the patch as soon as it is available.
Review System Logs
- Perform an audit of browser activity logs to identify any suspicious actions that could indicate exploitation of this vulnerability. This will help identify affected systems and users.
Update Detection Systems
- Adjust security monitoring systems to detect exploitation of this vulnerability. Consider updating SIEM rules to look for patterns related to the Type Confusion flaw and abnormal browser activity.
User Education
- Educate users on the importance of maintaining up-to-date software and safe browsing habits. Remind them to avoid clicking on untrusted links or visiting suspicious websites.
Monitor Threat Intelligence
- Stay updated on any further details released by Google regarding CVE-2025-10585, including any signs of more sophisticated exploitation techniques.
- Follow any additional guidance issued by Google, especially regarding newly discovered variants of this vulnerability.
Engage Google Support
- Reach out to Google for any additional details about the patch rollout and the scope of the vulnerabilities. In particular, confirm that all systems within the organization have received the necessary updates.

References