CVE-2021-37987 – This is a use-after-free vulnerability in Chrom... (How to Fix)

Q: What is the severity of CVE-2021-37987?

CVE-2021-37987 has a CVSS score of 8.8 (HIGH). This is a use-after-free vulnerability in Chrome's Network APIs that allows remote attackers to potentially exploit heap corruption via a crafted HTML page. Attackers could execute arbitrary code or cause browser crashes. All users running vulnerable Chrome versions are affected.

📋 TL;DR

This is a use-after-free vulnerability in Chrome's Network APIs that allows remote attackers to potentially exploit heap corruption via a crafted HTML page. Attackers could execute arbitrary code or cause browser crashes. All users running vulnerable Chrome versions are affected.

💻 Affected Systems

Products:

Google Chrome
Chromium-based browsers

Versions: All versions prior to 95.0.4638.54

Operating Systems: Windows, macOS, Linux, Android, Chrome OS

Default Config Vulnerable: ⚠️ Yes

Notes: All standard Chrome installations are vulnerable. Extensions or security settings don't mitigate this.

📦 What is this software?

Chrome by Google

Google Chrome is the world's most popular web browser, used by over 3 billion users globally across Windows, macOS, Linux, Android, and iOS platforms. As a Chromium-based browser developed by Google, Chrome dominates the browser market with approximately 65% market share, making it a critical compon...

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Debian Linux by Debian

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Debian Linux by Debian

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⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to full system compromise, data theft, or malware installation.

🟠

Likely Case

Browser crashes, denial of service, or limited code execution in sandboxed context.

🟢

If Mitigated

Browser crash with no further impact if sandboxing holds.

🌐 Internet-Facing: HIGH - Exploitable via visiting malicious websites without user interaction beyond page load.

🏢 Internal Only: MEDIUM - Requires user to visit malicious internal pages or click links.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires bypassing Chrome's sandbox and other security mitigations.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 95.0.4638.54 and later

Vendor Advisory: https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_19.html

Restart Required: Yes

Instructions:

1. Open Chrome 2. Click menu (three dots) → Help → About Google Chrome 3. Chrome will automatically check for and install updates 4. Click 'Relaunch' to restart with updated version

🔧 Temporary Workarounds

Disable JavaScript

all

Prevents exploitation by disabling JavaScript execution, but breaks most websites.

chrome://settings/content/javascript → Block

Use site isolation

all

Enable site isolation features to limit impact of potential exploitation.

chrome://flags/#enable-site-per-process → Enable

🧯 If You Can't Patch

Restrict browser usage to trusted websites only
Implement network filtering to block malicious HTML content

🔍 How to Verify

Check if Vulnerable:

Check Chrome version in menu → Help → About Google Chrome

Check Version:

google-chrome --version (Linux) or chrome://version

Verify Fix Applied:

Verify version is 95.0.4638.54 or higher

📡 Detection & Monitoring

Log Indicators:

Chrome crash reports
Unexpected process terminations
Sandbox escape attempts

Network Indicators:

Requests to known malicious domains serving crafted HTML
Unusual outbound connections after visiting websites

SIEM Query:

source="chrome" AND (event="crash" OR event="process_termination") AND version<"95.0.4638.54"

📊 Metadata

CVE ID: CVE-2021-37987

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: November 2, 2021

Last Updated: November 21, 2024

🔗 References

https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_19.html Vendor Advisory
https://crbug.com/1206928 Permissions Required,Vendor Advisory
https://www.debian.org/security/2022/dsa-5046 Third Party Advisory
https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_19.html Vendor Advisory
https://crbug.com/1206928 Permissions Required,Vendor Advisory
https://www.debian.org/security/2022/dsa-5046 Third Party Advisory

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🔗 Related Vulnerabilities

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