Windows PrintWorkflowUserSvc: Use after free allows local privilege escalation

Summary

A use-after-free flaw in the Windows PrintWorkflowUserSvc service allows an authorized local user to elevate privileges. The attacker needs a valid low-privileged account on the host and must overcome high attack complexity. Successful exploitation would give the attacker SYSTEM-level control, so multi-user systems such as terminal servers and shared workstations are most at risk.

Affected

• 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 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, including Server Core (10.0.26100.0 before 10.0.26100.33822)

Fixed in

• Install the November 2026 cumulative update for each affected version. The fixed build is the first build number listed as 'before' in the affected ranges above.
• KB article numbers: Unknown.

Workaround

• No workaround is documented. Installing the security update is the fix.
• Where patching must wait, validate the impact and then disable the PrintWorkflowUserSvc service on hosts that do not need UWP print workflow functions. Test first to confirm that printing still works.

Exploitation

• No public proof-of-concept exploit is known.
• No in-the-wild exploitation has been reported.
• CISA SSVC: exploitation none, not automatable, technical impact total.
• CVSS 3.1: 7.0 (High), vector AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H, exploit code maturity unproven.

Our recommendation

• Install the November 2026 Windows cumulative update on all affected systems and verify the build number against the MSRC advisory.
• Prioritise terminal servers, RDS hosts, shared PCs and any system with untrusted local users.
• Review local user accounts and remove unneeded access.
• Monitor for PrintWorkflowUserSvc crashes followed by process creation under NT AUTHORITY\SYSTEM.
• Recheck MSRC and NVD for exploit reports, as the status may change quickly.

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-2026-119928 msrc.microsoft.com
• CVE.org CVE Record CVE-2026-119928 www.cve.org
• VulDB entry 434330 vuldb.com
• Strix AI CVE-2026-119928 (third-party mirror) 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, 08:27.