Critical Microsoft Vulnerability Allows Remote Code Execution: Patch CVE-2026-24305 Immediately

A severe vulnerability in Microsoft Windows permits unauthorized remote code execution. Designated CVE-2026-24305, this flaw carries a CVSS v3.1 score of 9.8 (Critical). Attackers exploiting this vulnerability could gain full system control without user interaction. Microsoft confirmed the issue affects Windows 10 versions 22H2, 21H2, and Windows Server 2022. Earlier Windows versions may also be vulnerable.

Technical analysis reveals the weakness resides in the Windows TCP/IP stack. Specifically, improper handling of IPv6 fragmented packets triggers a heap-based buffer overflow. This allows attackers to craft malicious network packets that overwrite memory structures. Successful exploitation lets attackers run code with SYSTEM privileges. No authentication is required for exploitation. Network-adjacent attackers can trigger this flaw via local networks or VPN connections.

Microsoft released patches addressing CVE-2026-24305 in its July 2026 Patch Tuesday update. Administrators must immediately deploy security updates through Windows Update or the Microsoft Update Catalog. For systems requiring delayed patching, implement temporary mitigations: Block TCP port 3544 at network boundaries and disable IPv6 fragmentation support using PowerShell commands. Microsoft detected no active exploitation in the wild as of disclosure.

Vulnerability discovery occurred on May 12, 2026, through Microsoft's internal security team. Coordinated disclosure followed standard MSRC processes with patches released on July 8, 2026. Microsoft's Security Update Guide provides detailed technical advisories. Organizations should prioritize patching externally facing systems within 24 hours. Internal systems require remediation within 72 hours due to the high risk of wormable propagation. Failure to patch risks enterprise-wide compromise and data exfiltration.

Security teams must verify patch deployment using Microsoft Endpoint Configuration Manager or equivalent tools. Monitor network traffic for anomalous IPv6 packet patterns as potential exploitation indicators. Microsoft recommends reviewing STRIDE threat modeling principles for attack surface reduction. This vulnerability underscores the critical need for timely patch management cycles across all Windows environments.