CVE-2021-37976 Overview
CVE-2021-37976 is an inappropriate implementation vulnerability in the Memory component of Google Chrome prior to version 94.0.4606.71. This vulnerability allows a remote attacker to obtain potentially sensitive information from process memory by luring a victim to visit a specially crafted HTML page. The flaw exists due to missing authorization checks (CWE-862) in memory handling operations, enabling information disclosure attacks through malicious web content.
Critical Impact
This vulnerability is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, indicating confirmed active exploitation in the wild. Remote attackers can extract sensitive information from Chrome's process memory without authentication, requiring only that a user visit a malicious webpage.
Affected Products
- Google Chrome versions prior to 94.0.4606.71
- Fedora Project Fedora (versions 33, 34, 35)
- Debian Linux (versions 10.0, 11.0)
Discovery Timeline
- October 8, 2021 - CVE-2021-37976 published to NVD
- October 24, 2025 - Last updated in NVD database
Technical Details for CVE-2021-37976
Vulnerability Analysis
The vulnerability stems from an inappropriate implementation within Chrome's memory handling subsystem. When processing certain HTML content, the browser fails to properly authorize or validate memory access operations, allowing portions of process memory to be leaked to an attacker. This information disclosure vulnerability enables remote attackers to potentially access sensitive data stored in the browser's memory space, including session tokens, credentials, or other confidential information that may reside in process memory during normal browsing activities.
The attack requires user interaction in the form of visiting a crafted webpage, but no authentication or special privileges are required by the attacker to exploit this vulnerability.
Root Cause
The root cause is classified under CWE-862 (Missing Authorization). The Chrome memory implementation lacked proper authorization checks when handling certain operations triggered by web content. This missing validation allowed malicious HTML pages to trigger memory read operations that should have been restricted, resulting in the disclosure of sensitive process memory contents to the attacker.
Attack Vector
The attack vector is network-based, requiring the attacker to host or inject malicious HTML content that a victim must navigate to. The exploitation sequence typically involves:
- Attacker crafts a malicious HTML page designed to trigger the inappropriate memory implementation
- Victim visits the attacker-controlled or compromised website
- Chrome processes the malicious HTML content
- Due to missing authorization checks in memory handling, sensitive process memory is disclosed
- Attacker receives the leaked information, potentially including session data, cached credentials, or other sensitive content
The attack complexity is low, and while user interaction is required, no special privileges are needed for exploitation. The vulnerability has a high impact on confidentiality, though integrity and availability are not affected.
Detection Methods for CVE-2021-37976
Indicators of Compromise
- Unusual Chrome memory access patterns or unexpected process memory reads detected through endpoint monitoring
- Network traffic containing crafted HTML payloads designed to trigger memory disclosure
- Chrome crash reports or stability issues that may indicate exploitation attempts
- Suspicious outbound data exfiltration following visits to untrusted websites
Detection Strategies
- Monitor for Chrome browser versions prior to 94.0.4606.71 across the enterprise environment
- Implement web filtering to detect and block known malicious pages targeting this vulnerability
- Deploy endpoint detection and response (EDR) solutions capable of monitoring browser memory operations
- Utilize network intrusion detection systems (NIDS) to identify suspicious HTML payloads in web traffic
Monitoring Recommendations
- Enable Chrome's built-in crash reporting and review for patterns suggesting exploitation
- Monitor DNS and proxy logs for connections to known malicious domains distributing exploits
- Implement browser telemetry collection to track version compliance across endpoints
- Review security logs for anomalous Chrome process behavior or memory access events
How to Mitigate CVE-2021-37976
Immediate Actions Required
- Update Google Chrome to version 94.0.4606.71 or later immediately across all systems
- Enable automatic Chrome updates to ensure timely patching of future vulnerabilities
- For Fedora users, apply the security updates via the package manager as per the Fedora Package Announcements
- For Debian users, apply patches as documented in Debian Security Advisory DSA-5046
Patch Information
Google addressed this vulnerability in Chrome version 94.0.4606.71, released on September 30, 2021. The fix is documented in the Chrome Stable Update Blog. Additional technical details are available in the Chromium Bug Report. Given this vulnerability is listed in the CISA Known Exploited Vulnerabilities Catalog, organizations subject to CISA directives should prioritize remediation.
Workarounds
- Restrict access to untrusted websites through web proxy policies until patching is complete
- Consider using browser isolation technologies to contain potential exploitation attempts
- Implement strict Content Security Policy (CSP) headers on internal web applications
- Educate users about the risks of visiting untrusted websites while systems remain unpatched
# Verify Chrome version on Linux systems
google-chrome --version
# Expected output should show version 94.0.4606.71 or higher
# Update Chrome on Debian/Ubuntu-based systems
sudo apt update && sudo apt upgrade google-chrome-stable
# Update Chrome on Fedora systems
sudo dnf update chromium
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
