CVE-2021-30632 – This vulnerability allows remote attackers to e... (How to Fix)

Q: What is the severity of CVE-2021-30632?

CVE-2021-30632 has a CVSS score of 8.8 (HIGH). This vulnerability allows remote attackers to execute arbitrary code or cause heap corruption in Google Chrome by tricking users into visiting a malicious HTML page. It affects all Chrome users running versions prior to 93.0.4577.82. The exploit leverages an out-of-bounds write in the V8 JavaScript engine's JIT compiler.

📋 TL;DR

This vulnerability allows remote attackers to execute arbitrary code or cause heap corruption in Google Chrome by tricking users into visiting a malicious HTML page. It affects all Chrome users running versions prior to 93.0.4577.82. The exploit leverages an out-of-bounds write in the V8 JavaScript engine's JIT compiler.

💻 Affected Systems

Products:

Google Chrome
Chromium-based browsers

Versions: All versions prior to 93.0.4577.82

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

Default Config Vulnerable: ⚠️ Yes

Notes: All standard Chrome installations are vulnerable. Extensions or security settings do not mitigate this vulnerability.

📦 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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⚠️ Risk & Real-World Impact

🔴

Worst Case

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

🟠

Likely Case

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

🟢

If Mitigated

No impact if Chrome is fully patched or if exploit attempts are blocked by security controls.

🌐 Internet-Facing: HIGH - Attackers can host malicious pages on the internet and target any vulnerable Chrome user.

🏢 Internal Only: MEDIUM - Risk exists if internal users visit compromised internal sites or phishing pages.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Proof-of-concept code is publicly available. Exploitation requires user interaction (visiting a malicious page).

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 93.0.4577.82 and later

Vendor Advisory: https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop.html

Restart Required: Yes

Instructions:

1. Open Chrome. 2. Click the three-dot menu → Help → About Google Chrome. 3. Chrome will automatically check for and apply updates. 4. Restart Chrome when prompted.

🔧 Temporary Workarounds

Disable JavaScript

all

Prevents exploitation by disabling JavaScript execution, but breaks most website functionality.

chrome://settings/content/javascript → Block

Use Site Isolation

all

Enables Chrome's Site Isolation feature to limit impact of renderer process compromises.

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

🧯 If You Can't Patch

Restrict browser usage to trusted websites only.
Deploy network filtering to block known malicious domains and suspicious HTML content.

🔍 How to Verify

Check if Vulnerable:

Check Chrome version: If version is below 93.0.4577.82, the system is vulnerable.

Check Version:

On Chrome: chrome://version/ | On command line: google-chrome --version

Verify Fix Applied:

Confirm Chrome version is 93.0.4577.82 or higher after update.

📡 Detection & Monitoring

Log Indicators:

Chrome crash reports with V8 or heap corruption errors
Unexpected browser process termination

Network Indicators:

HTTP requests to domains hosting the exploit HTML page
Unusual outbound connections from Chrome processes

SIEM Query:

source="chrome_logs" AND ("V8" OR "heap corruption" OR "out of bounds")

📊 Metadata

CVE ID: CVE-2021-30632

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-787

Published: October 8, 2021

Last Updated: October 24, 2025

🔗 References

http://packetstormsecurity.com/files/172845/Chrome-JIT-Compiler-Type-Confusion.html Third Party Advisory,VDB Entry
https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop.html Release Notes
https://crbug.com/1247763 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4DDW7HAHTS3SDVXBQUY4SURELO5D4X7R/ Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PM7MOYYHJSWLIFZ4TPJTD7MSA3HSSLV2/ Release Notes
http://packetstormsecurity.com/files/172845/Chrome-JIT-Compiler-Type-Confusion.html Third Party Advisory,VDB Entry
https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop.html Release Notes
https://crbug.com/1247763 Permissions Required
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4DDW7HAHTS3SDVXBQUY4SURELO5D4X7R/ Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PM7MOYYHJSWLIFZ4TPJTD7MSA3HSSLV2/ Release Notes
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30632 US Government Resource

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