CVE-2021-30598 Overview
CVE-2021-30598 is a type confusion vulnerability in the V8 JavaScript engine used by Google Chrome versions prior to 92.0.4515.159. This vulnerability allows a remote attacker to execute arbitrary code inside the browser sandbox by enticing a user to visit a specially crafted HTML page. Type confusion vulnerabilities occur when code fails to verify object types before performing operations, leading to memory corruption and potential code execution.
Critical Impact
Remote attackers can achieve arbitrary code execution within the Chrome sandbox by exploiting this type confusion flaw in V8, potentially compromising user data and browser integrity.
Affected Products
- Google Chrome versions prior to 92.0.4515.159
- Fedora 33 (Chromium packages)
- Fedora 34 (Chromium packages)
- Fedora 35 (Chromium packages)
Discovery Timeline
- 2021-08-26 - CVE-2021-30598 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2021-30598
Vulnerability Analysis
This vulnerability exists in V8, Chrome's high-performance JavaScript and WebAssembly engine. Type confusion (CWE-843) occurs when a program allocates or initializes an object of one type but later accesses it as a different, incompatible type. In the context of V8, this can lead to memory corruption because JavaScript's dynamic typing allows objects to be treated differently at runtime than they were originally created.
When V8 incorrectly handles type information during JavaScript execution, an attacker can craft malicious JavaScript code embedded in an HTML page that triggers the confusion. This causes the engine to interpret memory regions incorrectly, potentially allowing the attacker to read or write arbitrary memory locations within the renderer process sandbox.
The network-based attack vector requires user interaction—specifically, the victim must navigate to a malicious webpage. Once triggered, the vulnerability enables arbitrary code execution within Chrome's sandbox environment.
Root Cause
The root cause is a type confusion flaw in V8's handling of JavaScript objects. V8 uses various optimization techniques including type specialization and inline caching to improve performance. When the engine's assumptions about object types prove incorrect during execution, it can lead to operations being performed on memory structures that don't match the expected layout, resulting in exploitable memory corruption.
Attack Vector
The attack is executed remotely over the network when a victim visits an attacker-controlled webpage. The malicious page contains specially crafted JavaScript that exploits the type confusion in V8. The attack flow typically involves:
- Attacker creates a malicious HTML page with exploit JavaScript code
- Victim navigates to the malicious page (via phishing, malvertising, or watering hole attacks)
- V8 engine processes the malicious JavaScript, triggering the type confusion
- Memory corruption occurs, enabling arbitrary code execution within the sandbox
- Attacker gains control within the renderer process sandbox
The vulnerability is triggered through crafted JavaScript that manipulates object types in a way that causes V8 to misinterpret memory structures. Technical details can be found in Chromium Bug Report #1234764.
Detection Methods for CVE-2021-30598
Indicators of Compromise
- Unusual browser crashes or renderer process terminations that could indicate exploitation attempts
- Network traffic to known malicious domains hosting exploit pages
- Suspicious JavaScript execution patterns in browser telemetry or endpoint logs
- Abnormal memory consumption or process behavior in Chrome renderer processes
Detection Strategies
- Monitor for Chrome versions prior to 92.0.4515.159 deployed in your environment
- Implement network-based detection for known exploit page signatures and malicious JavaScript patterns
- Deploy endpoint detection solutions that can identify exploitation of browser vulnerabilities
- Review browser crash reports for patterns consistent with memory corruption exploitation
Monitoring Recommendations
- Enable Chrome's built-in crash reporting to identify potential exploitation attempts
- Monitor endpoint telemetry for suspicious renderer process behavior
- Implement web filtering to block access to known malicious sites distributing browser exploits
- Track browser version compliance across the enterprise to identify unpatched installations
How to Mitigate CVE-2021-30598
Immediate Actions Required
- Update Google Chrome to version 92.0.4515.159 or later immediately
- Enable automatic updates to ensure timely deployment of security patches
- For Fedora users, apply the latest Chromium package updates via your package manager
- Consider deploying browser isolation solutions to contain potential sandbox escapes
Patch Information
Google released a fix for this vulnerability in Chrome version 92.0.4515.159 as announced in the Google Chrome Update Announcement. Fedora has also released updated packages addressing this vulnerability for Fedora 33, 34, and 35 distributions.
For enterprise deployments, use Chrome's enterprise management features to force updates or block vulnerable versions from running.
Workarounds
- Disable JavaScript execution in Chrome (significantly impacts functionality but eliminates the attack vector)
- Use browser isolation or virtualized browsing for high-risk activities
- Implement strict web content filtering to block potentially malicious sites
- Consider using alternative browsers temporarily until patches can be deployed
# Verify Chrome version on Linux systems
google-chrome --version
# Update Chrome on Fedora
sudo dnf update chromium
# Force Chrome to check for updates (Windows)
# Navigate to chrome://settings/help in the browser
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
