CVE-2021-30624 – CVE-2021-30624 is a use-after-free vulnerabilit... (How to Fix)

Q: What is the severity of CVE-2021-30624?

CVE-2021-30624 has a CVSS score of 8.8 (HIGH). CVE-2021-30624 is a use-after-free vulnerability in Chromium's Autofill feature that allows attackers to execute arbitrary code or cause a denial of service. This affects all Chromium-based browsers including Google Chrome, Microsoft Edge, and others. Users who haven't updated their browsers are vulnerable to exploitation.

📋 TL;DR

CVE-2021-30624 is a use-after-free vulnerability in Chromium's Autofill feature that allows attackers to execute arbitrary code or cause a denial of service. This affects all Chromium-based browsers including Google Chrome, Microsoft Edge, and others. Users who haven't updated their browsers are vulnerable to exploitation.

💻 Affected Systems

Products:

Google Chrome
Microsoft Edge
Chromium-based browsers

Versions: Chrome versions before 93.0.4577.63, Edge versions before 93.0.961.38

Operating Systems: Windows, Linux, macOS, Android, iOS

Default Config Vulnerable: ⚠️ Yes

Notes: All default configurations are vulnerable. Autofill must be enabled (default setting).

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, data theft, or ransomware deployment.

🟠

Likely Case

Browser crash (denial of service) or limited code execution within browser sandbox.

🟢

If Mitigated

Minimal impact if browser sandboxing works properly, potentially just a tab crash.

🌐 Internet-Facing: HIGH - Browser vulnerabilities are directly exposed to web content.

🏢 Internal Only: MEDIUM - Still vulnerable to internal malicious sites or compromised internal resources.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Use-after-free vulnerabilities typically require specific memory manipulation knowledge. No public exploits known.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Chrome 93.0.4577.63, Edge 93.0.961.38

Vendor Advisory: https://chromereleases.googleblog.com/2021/08/stable-channel-update-for-desktop_31.html

Restart Required: Yes

Instructions:

1. Open browser settings 2. Navigate to 'About Chrome/Edge' 3. Browser will automatically check for and install updates 4. Restart browser when prompted

🔧 Temporary Workarounds

Disable Autofill

all

Temporarily disable the Autofill feature to mitigate the vulnerability

Use alternative browser

all

Switch to non-Chromium browser until patched

🧯 If You Can't Patch

Implement network filtering to block malicious websites
Use application control to restrict browser execution in high-risk environments

🔍 How to Verify

Check if Vulnerable:

Check browser version in settings > About Chrome/Edge. If version is below 93.0.4577.63 (Chrome) or 93.0.961.38 (Edge), you are vulnerable.

Check Version:

chrome://version/ or edge://version/

Verify Fix Applied:

Confirm browser version is 93.0.4577.63 or higher for Chrome, 93.0.961.38 or higher for Edge.

📡 Detection & Monitoring

Log Indicators:

Browser crash logs with memory access violations
Unexpected browser process termination

Network Indicators:

Unusual outbound connections from browser after visiting websites
Traffic to known exploit hosting domains

SIEM Query:

source="browser_logs" AND (event="crash" OR event="access_violation") AND process="chrome.exe" OR process="msedge.exe"

📊 Metadata

CVE ID: CVE-2021-30624

CVSS v3 Score: 8.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-416

Published: September 3, 2021

Last Updated: November 21, 2024

🔗 References

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