Windows srvnet.sys (SMB Server): Remote code execution via race condition

Summary

A race condition (CWE-362) in the SMB server network transport driver srvnet.sys of Windows allows an authorized attacker to execute code over the network. Exploitation requires winning a race, which Microsoft's CVSS rating reflects as high attack complexity. Successful exploitation could give the attacker full control over the affected system, including domain controllers and file servers that expose SMB on TCP/445.

Affected

• Windows 10 Version 1809 (before 10.0.17763.9487)
• Windows 10 Version 21H2 (before 10.0.19044.7846)
• Windows 10 Version 22H2 (before 10.0.19045.7846)
• Windows 11 Version 23H2 (before 10.0.22631.7711)
• Windows 11 Version 24H2 (before 10.0.26100.9974)
• Windows 11 Version 25H2 (before 10.0.26200.9974)
• Windows 11 Version 26H1 (before 10.0.28000.3501)
• Windows 11 Version 26H2 (before 10.0.26300.9974)
• Windows Server 2019, including Server Core (before 10.0.17763.9487)
• Windows Server 2022 (before 10.0.20348.5870)
• Windows Server 2025, including Server Core (before 10.0.26100.33822)
• Build numbers are taken from the CVE record and must be checked against the MSRC table.

Fixed in

• Security updates released with Patch Tuesday of November 10, 2026 (fixed builds as listed above)
• KB numbers per build: Unknown.

Workaround

• Unknown. No Microsoft workaround was found in the sources reviewed.
• General interim measure (not from Microsoft): restrict TCP/445 to required internal hosts and block SMB from the internet.

Exploitation

• No exploitation observed according to the sources reviewed.
• No public proof of concept found.
• CISA SSVC: exploitation none, not automatable, total technical impact.
• Microsoft rates exploit maturity as unproven (E:U).

Our recommendation

• Identify all Windows 10, Windows 11 and Windows Server hosts on the affected builds, prioritizing domain controllers and file servers.
• Install the November 2026 security updates on these systems after confirming the KB for each build in the MSRC table.
• Verify that SMB (TCP/445) is reachable only from internal hosts that need it, and disable SMB where it is not required.
• Monitor for a public proof of concept or a CISA KEV entry and recheck the NVD record once analysis is complete.

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

• MSRC Security Update Guide: CVE-2026-113825 msrc.microsoft.com
• CVE.org record CVE-2026-113825 www.cve.org
• Strix: affected builds CVE-2026-113825 www.strix.ai
• CrowdStrike: Patch Tuesday analysis November 2026 www.crowdstrike.com
• Splashtop: Patch Tuesday November 2026 www.splashtop.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, 05:54.