CVE-2020-6418 Overview
CVE-2020-6418 is a type confusion vulnerability in the V8 JavaScript engine used by Google Chrome prior to version 80.0.3987.122. This vulnerability allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. The flaw exists in Chrome's V8 JavaScript engine, which is responsible for executing JavaScript code in the browser. Type confusion vulnerabilities occur when code doesn't verify the type of an object before performing operations on it, leading to memory corruption that can be leveraged for arbitrary code execution.
Critical Impact
This vulnerability has been actively exploited in the wild and is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog. Successful exploitation allows remote attackers to execute arbitrary code in the context of the browser process, potentially leading to complete system compromise.
Affected Products
- Google Chrome versions prior to 80.0.3987.122
- Fedora 30 and 31 (via bundled Chromium)
- Red Hat Enterprise Linux Desktop 6.0
- Red Hat Enterprise Linux Server 6.0
- Red Hat Enterprise Linux Workstation 6.0
- Debian Linux 9.0 and 10.0
Discovery Timeline
- February 24, 2020 - Google releases Chrome 80.0.3987.122 addressing this vulnerability
- February 27, 2020 - CVE-2020-6418 published to NVD
- October 24, 2025 - Last updated in NVD database
Technical Details for CVE-2020-6418
Vulnerability Analysis
CVE-2020-6418 is a type confusion vulnerability that occurs in the V8 JavaScript engine's handling of JSCreate operations. The vulnerability stems from improper type tracking during JavaScript execution, where the engine fails to correctly handle side effects that can change object types during certain operations. This flaw allows an attacker to craft malicious JavaScript code that tricks the V8 engine into treating an object as a different type than it actually is, leading to heap corruption.
The vulnerability is particularly dangerous because V8 performs Just-In-Time (JIT) compilation to optimize JavaScript execution. During this optimization process, incorrect type assumptions can persist, allowing attackers to corrupt memory in predictable ways. This heap corruption primitive can then be leveraged to achieve arbitrary read/write capabilities, ultimately leading to remote code execution.
Root Cause
The root cause of CVE-2020-6418 lies in how V8's optimizing compiler (TurboFan) handles side effects during JSCreate operations. When JavaScript code creates new objects, certain side effects can modify the feedback that TurboFan uses to make type assumptions. If these side effects change the expected type of an object after TurboFan has already made its optimization decisions, but before the object is actually used, a type confusion condition occurs.
Specifically, the vulnerability is triggered when the JSCreate operation's side effects cause the compiled code to operate on an object with an unexpected type. This mismatch between expected and actual types results in incorrect memory access patterns, leading to heap corruption that can be exploited for code execution.
Attack Vector
The attack vector for CVE-2020-6418 is network-based and requires user interaction. An attacker can exploit this vulnerability by hosting a malicious webpage containing specially crafted JavaScript code designed to trigger the type confusion. When a victim visits the malicious page using a vulnerable version of Google Chrome, the JavaScript executes in the browser's renderer process.
The attack typically follows this pattern: The malicious JavaScript first sets up the heap in a controlled state, then triggers the type confusion through carefully crafted object creation and manipulation. Once heap corruption is achieved, the attacker can use standard exploitation techniques to gain code execution within the browser sandbox. Additional sandbox escape vulnerabilities may be chained to achieve full system compromise.
The exploitation mechanism involves manipulating JavaScript objects and their type feedback to trigger the vulnerable code path in V8's JSCreate handling. Technical details of the exploitation technique are documented in the Packet Storm Security Exploit publication.
Detection Methods for CVE-2020-6418
Indicators of Compromise
- Unusual browser crashes or renderer process terminations, particularly when visiting untrusted websites
- Chrome crash reports referencing V8 or JavaScript execution failures
- Detection of known exploit signatures in network traffic or memory dumps
- Anomalous JavaScript execution patterns in browser logs
Detection Strategies
- Monitor for Chrome versions below 80.0.3987.122 across the enterprise using software inventory tools
- Implement network-based detection rules for known exploitation patterns targeting V8 type confusion
- Deploy endpoint detection and response (EDR) solutions capable of detecting heap corruption exploitation techniques
- Utilize browser telemetry to identify unusual JavaScript execution behavior
Monitoring Recommendations
- Enable Chrome's built-in crash reporting and monitor for V8-related crashes
- Implement web proxy logging to track access to known malicious domains
- Configure SIEM rules to alert on multiple browser crashes from a single endpoint
- Monitor for child processes spawned by browser renderer processes, which may indicate successful exploitation
How to Mitigate CVE-2020-6418
Immediate Actions Required
- Update Google Chrome to version 80.0.3987.122 or later immediately across all systems
- Apply vendor-specific patches for affected Linux distributions (Fedora, Red Hat, Debian)
- Implement network-level blocking of known malicious domains associated with this exploit
- Consider temporarily restricting access to untrusted websites until patching is complete
Patch Information
Google addressed CVE-2020-6418 in Chrome version 80.0.3987.122, released on February 24, 2020. The fix corrects the type tracking issue in V8's JSCreate operation handling to prevent the type confusion condition. Organizations should update to this version or later to remediate the vulnerability.
Vendor security advisories and patches are available:
- Google Chrome Update Announcement
- Red Hat Security Errata RHSA-2020:0738
- Debian Security Advisory DSA-4638
- Gentoo GLSA 2020-03-08
Workarounds
- Disable JavaScript in Chrome temporarily through browser settings (chrome://settings/content/javascript), though this significantly impacts web functionality
- Use browser isolation solutions to execute untrusted content in isolated environments
- Implement strict Content Security Policy headers on internal web applications to limit JavaScript execution
- Consider using alternative browsers temporarily until Chrome can be updated
# Verify Chrome version to confirm patch status
google-chrome --version
# Expected output: Google Chrome 80.0.3987.122 or higher
# For enterprise deployment, update Chrome using package managers
# Red Hat/CentOS/Fedora
sudo yum update chromium
# Debian/Ubuntu
sudo apt-get update && sudo apt-get upgrade chromium-browser
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
