Windows IKE Extension Double Free Remote Code Execution Vulnerability (CVE-2026-33824)

Affected Vendors

microsoft

Affected Components

windows, windows_server

Published Date

2026-04-14

Executive & SecOps Summary

SECOPS ASSESSMENT

Affected Scope

Internet Key Exchange (IKE) Extension service running on Microsoft Windows and Windows Server operating systems

Impact

An unauthenticated remote attacker can execute arbitrary code with system/kernel privileges over the network by sending specially crafted IKE packets

Mitigation

Apply the official Microsoft security updates immediately, and restrict external access to IKE/IPsec ports (UDP 500/4500) as a temporary workaround

Affected Products & Version Scope

All supported versions of Microsoft Windows and Windows Server with IKE Extension enabled

Remediation & Live Workaround Commands

PATCH & WORKAROUND

1. Apply Official Security Patches

Deploy the latest cumulative security updates provided by Microsoft immediately.

Microsoft MSRC Security Update Guide

2. Temporary Mitigation (Workaround)

If patching cannot be performed immediately, restrict inbound IKE/IPsec traffic at the host or network level.

Block Inbound IKE Ports via Windows Firewall (PowerShell):

powershell

# Block inbound UDP 500 (IKE) and UDP 4500 (IPsec NAT-T) from untrusted networks
New-NetFirewallRule -DisplayName "Block-IKE-Inbound-UDP500" -Direction Inbound -Action Block -Protocol UDP -LocalPort 500
New-NetFirewallRule -DisplayName "Block-IKE-Inbound-UDP4500" -Direction Inbound -Action Block -Protocol UDP -LocalPort 4500

Network-Level Mitigation:

Restrict inbound UDP 500 and UDP 4500 traffic at the perimeter firewall to authorized VPN gateways only.
Enable IPS signatures designed to detect anomalous IKE negotiation payloads.

Recommended Security Control & Mitigation Partner

NordLayer / Zero-Trust Network Access

This vulnerability is actively exploited in the wild; prioritize immediate patching or restrict external IKE/IPsec port exposure.

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Technical Root Cause & Exploitation Mechanics

CVE-2026-33824 is a critical Double Free vulnerability (CWE-415) residing within the Windows IKE (Internet Key Exchange) Extension module.

The vulnerability can be exploited remotely without authentication. When the IKE service processes a maliciously crafted negotiation request, a flaw in its memory management logic causes an already freed memory pointer to be freed a second time (Double Free).

This memory corruption allows attackers to manipulate the heap layout, bypass modern exploit mitigations, and achieve Remote Code Execution (RCE). Given its CVSS 3.1 score of 9.8 and its active exploitation status in the wild (CISA KEV), this vulnerability poses an immediate threat to enterprise perimeters.

Official Vendor Advisories & References

NVD Original English Description

Double free in Windows IKE Extension allows an unauthorized attacker to execute code over a network.

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33824

Source: secure@microsoft.com · Vendor Advisory

https://unit42.paloaltonetworks.com/autonomous-ai-cyber-attack-campaign/

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 · Third Party Advisory

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-33824

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 · US Government Resource

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