Windows Print Spooler: Local privilege escalation via TOCTOU race condition

Summary

A time-of-check time-of-use (TOCTOU) race condition in Windows Print Spooler Components allows an authorized local user to elevate privileges. An attacker needs a foothold on the affected system first, for example through a compromised user account, and the attack complexity is high. Successful exploitation could give an attacker higher privileges on the system, which matters most on servers and domain controllers where the Print Spooler runs.

Affected

• Windows 10 Version 1607 (10.0.14393.0 before 10.0.14393.9688)
• Windows 10 Version 1809 (10.0.17763.0 before 10.0.17763.9487)
• 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)
• Windows 11 Version 25H2 (10.0.26200.0 before 10.0.26200.9974)
• Windows 11 Version 26H1 (10.0.28000.0 before 10.0.28000.3501)
• Windows 11 Version 26H2 (10.0.26300.0 before 10.0.26300.9974)
• Windows Server 2016, including Server Core (10.0.14393.0 before 10.0.14393.9688)
• Windows Server 2019, including Server Core (10.0.17763.0 before 10.0.17763.9487)
• Windows Server 2022 (10.0.20348.0 before 10.0.20348.5870)
• Windows Server 2025: Unknown (not listed in the official CVE record)

Fixed in

• Microsoft November 2026 security update (released 2026-11-10)
• Fixed builds as listed in the affected section; KB numbers: Unknown (check the MSRC page)

Workaround

• Unknown. No Microsoft workaround was found in the sources.
• Disabling the Print Spooler service is a general option on systems that do not need printing, but it is not confirmed as a mitigation for this CVE.

Exploitation

• The CVE record uses exploit maturity E:U (unproven) and report confidence RC:C (confirmed).
• Talos reports that Microsoft lists one vulnerability from the November 2026 release as exploited in the wild, but does not name it in the post. Whether this CVE is affected is Unknown; check the MSRC Exploited flag.
• CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
• No public proof of concept was found in the research. NVD analysis was pending and no CISA KEV entry was found.

Our recommendation

• Install the Microsoft November 2026 security update on all affected Windows clients and servers, starting with domain controllers and file servers.
• Check the MSRC page for the KB numbers and the exploited status, and move the patch up if exploitation is confirmed.
• On servers and PCs that do not need printing, consider disabling the Print Spooler service after testing.
• Restrict local accounts, review privileged accounts and monitor for unexpected privilege changes or new services.

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

• Microsoft Security Update Guide: CVE-2026-112791 msrc.microsoft.com
• CVE.org record CVE-2026-112791 www.cve.org
• Talos: Microsoft Patch Tuesday for November 2026 blog.talosintelligence.com
• Qualys: Microsoft Patch Tuesday November 2026 review blog.qualys.com
• Strix mirror (unverified version data) www.strix.ai

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, 09:17.