CVE-2021-37997 – This is a use-after-free vulnerability in Googl... (How to Fix)

Q: What is the severity of CVE-2021-37997?

CVE-2021-37997 has a CVSS score of 8.8 (HIGH). This is a use-after-free vulnerability in Google Chrome's sign-in functionality that allows remote attackers to potentially exploit heap corruption. Attackers can trigger this by convincing users to sign into Chrome and visit a crafted HTML page. All Chrome users prior to version 95.0.4638.69 are affected.

📋 TL;DR

This is a use-after-free vulnerability in Google Chrome's sign-in functionality that allows remote attackers to potentially exploit heap corruption. Attackers can trigger this by convincing users to sign into Chrome and visit a crafted HTML page. All Chrome users prior to version 95.0.4638.69 are affected.

💻 Affected Systems

Products:

Google Chrome

Versions: All versions prior to 95.0.4638.69

Operating Systems: Windows, macOS, Linux, Chrome OS

Default Config Vulnerable: ⚠️ Yes

Notes: Requires user to sign into Chrome and visit a malicious HTML page.

📦 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...

Learn more about Chrome →

⚠️ Risk & Real-World Impact

🔴

Worst Case

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

🟠

Likely Case

Browser crash, memory corruption, or limited code execution within the Chrome sandbox.

🟢

If Mitigated

No impact if Chrome is updated to patched version or if users avoid signing into Chrome and visiting untrusted sites.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires user interaction (signing in and visiting malicious page).

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 95.0.4638.69

Vendor Advisory: https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_28.html

Restart Required: Yes

Instructions:

1. Open Chrome. 2. Click the three-dot menu. 3. Go to Help > About Google Chrome. 4. Chrome will automatically check for and install updates. 5. Click Relaunch to restart Chrome.

🔧 Temporary Workarounds

Disable Chrome Sign-In

all

Prevent users from signing into Chrome to remove the vulnerable code path.

chrome://flags/#account-consistency
Set to 'Disabled'

Use Chrome Enterprise Policies

all

Deploy policies to disable sign-in or restrict browser usage.

🧯 If You Can't Patch

Restrict users from signing into Chrome on vulnerable systems.
Implement network filtering to block malicious HTML pages and restrict browser usage to trusted sites only.

🔍 How to Verify

Check if Vulnerable:

Check Chrome version: If version is less than 95.0.4638.69, system is vulnerable.

Check Version:

google-chrome --version

Verify Fix Applied:

Confirm Chrome version is 95.0.4638.69 or higher.

📡 Detection & Monitoring

Log Indicators:

Chrome crash reports with memory corruption signatures
Unexpected sign-in events followed by crashes

Network Indicators:

HTTP requests to known malicious domains hosting crafted HTML
Unusual outbound connections after sign-in

SIEM Query:

source="chrome" AND (event="crash" OR event="signin") AND version<"95.0.4638.69"

📊 Metadata

CVE ID: CVE-2021-37997

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 23, 2021

Last Updated: November 21, 2024

🔗 References

https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_28.html Release Notes,Vendor Advisory
https://crbug.com/1259864 Permissions Required,Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3W46HRT2UVHWSLZB6JZHQF6JNQWKV744/
https://www.debian.org/security/2022/dsa-5046 Third Party Advisory
https://chromereleases.googleblog.com/2021/10/stable-channel-update-for-desktop_28.html Release Notes,Vendor Advisory
https://crbug.com/1259864 Permissions Required,Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3W46HRT2UVHWSLZB6JZHQF6JNQWKV744/
https://www.debian.org/security/2022/dsa-5046 Third Party Advisory

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🔗 Related Vulnerabilities

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