CVE-2025-3620: Google Chrome Use After Free Vulnerability

CVE-2025-3620 Overview

CVE-2025-3620 is a use-after-free vulnerability in the USB component of Google Chrome versions prior to 135.0.7049.95. A remote attacker can exploit heap corruption by serving a crafted HTML page to a victim. Chromium rates this issue as High severity, and successful exploitation can lead to arbitrary code execution within the renderer process. The vulnerability is tracked under CWE-416 and requires user interaction, such as visiting a malicious website. Google addressed the flaw in the Stable channel update for Desktop released in April 2025.

Critical Impact

Remote attackers can trigger heap corruption through a crafted HTML page, potentially leading to code execution in the browser context.

Affected Products

• Google Chrome on Windows prior to 135.0.7049.95
• Google Chrome on macOS prior to 135.0.7049.95
• Google Chrome on Linux prior to 135.0.7049.95

Discovery Timeline

• 2025-04-16 - CVE-2025-3620 published to NVD
• 2025-04-23 - Last updated in NVD database

References: Google Chrome Update Blog, Chromium Issue Tracker Entry.

Technical Details for CVE-2025-3620

Vulnerability Analysis

The flaw resides in Chrome's USB subsystem, which exposes WebUSB functionality to web content. A use-after-free condition occurs when the implementation retains a reference to a heap object after that object has been deallocated. When the freed memory is reallocated for attacker-controlled data, subsequent dereferences operate on corrupted state. This primitive enables heap corruption that an attacker can shape into a control-flow hijack inside the renderer process. Chrome's sandbox limits direct system impact, but renderer compromise is typically chained with a sandbox escape for full code execution on the host.

Root Cause

The root cause is improper object lifetime management within the USB component [CWE-416]. Code paths handling USB device state release or destroy an object while another reference remains live. Web content can drive these paths through WebUSB-related JavaScript APIs and timing of device events, leading to access of freed memory.

Attack Vector

Exploitation requires a victim to load a crafted HTML page in a vulnerable Chrome build. The attacker hosts JavaScript that manipulates USB-related objects to trigger the dangling reference, then sprays the heap to reclaim the freed allocation with controlled data. Subsequent operations on the stale pointer pivot execution into attacker-controlled memory.

No verified public proof-of-concept is available. See the Chromium Issue Tracker Entry for any disclosed technical details once restrictions are lifted.

Detection Methods for CVE-2025-3620

Indicators of Compromise

• Chrome renderer process crashes with heap corruption signatures shortly after visiting an untrusted page.
• Unexpected child processes spawned by chrome.exe or the Chrome helper processes on macOS and Linux.
• Outbound connections from Chrome to low-reputation domains immediately preceding renderer instability.

Detection Strategies

• Inventory installed Chrome versions across endpoints and flag any build earlier than 135.0.7049.95.
• Hunt for browser exploitation patterns such as renderer processes performing file system writes to autostart locations or launching shells.
• Correlate web proxy logs with endpoint telemetry to identify users who visited suspicious pages around crash events.

Monitoring Recommendations

• Forward Chrome crash reports and Windows Error Reporting events to a central log store for review.
• Monitor process lineage where Chrome renderer or GPU processes spawn cmd.exe, powershell.exe, bash, or other interpreters.
• Track WebUSB API usage on managed fleets through enterprise policy reporting where applicable.

How to Mitigate CVE-2025-3620

Immediate Actions Required

• Update Google Chrome to version 135.0.7049.95 or later on all managed endpoints.
• Restart Chrome after the update so the patched binaries are loaded into memory.
• Validate version compliance using endpoint management tooling and quarantine non-compliant hosts.

Patch Information

Google released the fix in the Stable channel update for Desktop on April 15, 2025. Details are published in the Google Chrome Update Blog. Chromium-based browsers that share the same upstream code, such as Microsoft Edge and Brave, should be updated to the corresponding patched releases issued by their vendors.

Workarounds

• Disable WebUSB via enterprise policy by setting DefaultWebUsbGuardSetting to 2 until patching is complete.
• Restrict browsing to trusted sites through web filtering while the rollout is in progress.
• Apply the WebUsbBlockedForUrls policy to block WebUSB access on high-risk URL patterns.

# Configuration example - Chrome enterprise policy (Linux JSON policy)
# /etc/opt/chrome/policies/managed/disable_webusb.json
{
  "DefaultWebUsbGuardSetting": 2,
  "WebUsbBlockedForUrls": ["*"]
}