Windows TCP/IP: Double free leads to local privilege escalation

Summary

A double free weakness (CWE-415) in the Windows TCP/IP networking stack allows a local attacker with low privileges to elevate privileges to a higher level, with high impact on confidentiality, integrity and availability. Exploitation requires a local, low-privilege foothold and a high-complexity attack. The main risk is a second-stage escalation after phishing or malware on a workstation or a shared terminal server.

Affected

• Windows 10 Version 21H2: 10.0.19044.0 before 10.0.19044.7846
• Windows 10 Version 22H2: 10.0.19045.0 before 10.0.19045.7846
• Windows 11 Version 23H2: 10.0.22631.0 before 10.0.22631.7711
• Windows 11 Version 24H2: 10.0.26100.0 before 10.0.26100.9974 (per CVE record; fix level unverified)
• Windows 11 Version 25H2: 10.0.26200.0 before 10.0.26200.9974 (per CVE record; fix level unverified)
• Windows 11 Version 26H1: 10.0.28000.0 before 10.0.28000.3501 (per CVE record; fix level unverified)
• Windows 11 Version 26H2: 10.0.26300.0 before 10.0.26300.9974 (per CVE record; fix level unverified)
• Windows Server 2022: 10.0.20348.0 before 10.0.20348.5870 (per CVE record; fix level unverified)
• Windows Server 2025 (including Server Core): 10.0.26100.0 before 10.0.26100.33822 (per CVE record; fix level unverified)

Fixed in

• Windows 10 Version 21H2: 10.0.19044.7846 or later
• Windows 10 Version 22H2: 10.0.19045.7846 or later
• Windows 11 Version 23H2: 10.0.22631.7711 or later
• Other listed versions: fix levels are not confirmed by the vendor in the sources available; check the MSRC update guide.

Workaround

No vendor workaround known. Apply the official security update.

Exploitation

• Exploited in the wild: not known.
• CISA SSVC: exploitation none, not automatable, technical impact total.
• Public proof-of-concept: none found in the sources checked (not a complete check).

Our recommendation

• Apply the official Microsoft security update for the affected Windows versions through the monthly patch cycle, with medium-high priority.
• Verify the exact fixed build numbers for your versions in the MSRC Security Update Guide, because some values were not confirmed by the vendor.
• Check whether Windows 10 21H2 and 22H2 devices are enrolled in Extended Security Updates; devices without ESU will not receive this fix.
• Limit local accounts and restrict RDP and terminal services access, and monitor for signs of privilege escalation on workstations and servers.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• CVE Record CVE-2026-96969 (CNA Microsoft) www.cve.org
• MSRC Security Update Guide CVE-2026-96969 msrc.microsoft.com
• OffSeq Radar: exploitation status (aggregator) radar.offseq.com
• Strix: additional build list (aggregator, unverified) www.strix.ai
• Vulners: possible related record CVE-2026-83842 vulners.com

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 07:33.