CVE-2024-21326
📋 TL;DR
This vulnerability in Microsoft Edge allows attackers to gain elevated privileges on affected systems by exploiting a use-after-free memory corruption flaw. It affects users running vulnerable versions of Microsoft Edge on Windows systems. Successful exploitation could lead to complete system compromise.
💻 Affected Systems
- Microsoft Edge (Chromium-based)
📦 What is this software?
Edge Chromium by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover with SYSTEM/root privileges, enabling installation of persistent malware, data theft, and lateral movement across networks.
Likely Case
Local privilege escalation allowing attackers to bypass security controls, install unauthorized software, and access sensitive data on the compromised system.
If Mitigated
Limited impact with proper application sandboxing and exploit mitigations, potentially reduced to denial of service or limited data exposure.
🎯 Exploit Status
Requires user interaction but no authentication. Exploitation leverages CWE-416 (Use After Free) memory corruption vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Microsoft Edge version 121.0.2277.128 or later
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21326
Restart Required: Yes
Instructions:
1. Open Microsoft Edge. 2. Click Settings (three dots) → Help and feedback → About Microsoft Edge. 3. Browser will automatically check for and install updates. 4. Restart Edge when prompted. 5. Verify version is 121.0.2277.128 or higher.
🔧 Temporary Workarounds
Disable Edge browser
windowsTemporarily disable Microsoft Edge as default browser to reduce attack surface
Set default browser to alternative (Chrome, Firefox) via Windows Settings → Apps → Default apps
Enable Enhanced Security Mode
windowsEnable Edge's Enhanced Security Mode for additional protection
Edge Settings → Privacy, search, and services → Enable Enhanced Security Mode
🧯 If You Can't Patch
- Implement application control policies to restrict execution of unauthorized binaries
- Deploy endpoint detection and response (EDR) solutions with memory protection capabilities
🔍 How to Verify
Check if Vulnerable:
Check Edge version: Open Edge → Settings → About Microsoft Edge. If version is below 121.0.2277.128, system is vulnerable.Check Version:
msedge --versionVerify Fix Applied:
Confirm Edge version is 121.0.2277.128 or higher in About Microsoft Edge page.📡 Detection & Monitoring
Log Indicators:
- Edge crash reports with memory corruption signatures
- Unexpected privilege escalation events in Windows Security logs
- Suspicious child processes spawned from Edge
Network Indicators:
- Connections to known malicious domains from Edge process
- Unusual outbound traffic patterns following Edge usage
SIEM Query:
EventID=4688 AND ParentProcessName="msedge.exe" AND NewProcessName IN ("cmd.exe", "powershell.exe", "reg.exe")