CVE tracker / CVE-2026-83997
CVE-2026-83997
CVE-2026-83997 is the Windows Message Queuing Remote Code Execution Vulnerability. Microsoft rates it Important, CVSS 8.1. It is not in CISA's Known Exploited Vulnerabilities catalog. Published September 8, 2026.
Risk summary
HighRemote Code Execution
8.1
CVSS v3 base
0.7%
EPSS: chance of exploitation in 30 days
High
Severity
Important
Microsoft's rating
Unlikely
Microsoft: exploitation
No
In CISA KEV
Microsoft describes it: “Use after free in Windows Message Queuing allows an unauthorized attacker to execute code over a network.”
How to fix it
Microsoft lists 18 affected products and the update that fixes each:
- KB5122871 · fixed build 10.0.26100.33438
Windows Server 2025, Windows Server 2025 (Server Core installation) - KB5122878 · fixed build 10.0.19045.7725, 10.0.19044.7725
Windows 10 Version 22H2 for x64-based Systems, Windows 10 Version 22H2 for 32-bit Systems, Windows 10 Version 22H2 for ARM64-based Systems, Windows 10 Version 21H2 for x64-based Systems, Windows 10 Version 21H2 for ARM64-based Systems, and 1 more - KB5122880 · fixed build 10.0.22631.7582
Windows 11 Version 23H2 for x64-based Systems, Windows 11 Version 23H2 for ARM64-based Systems - KB5122882 · fixed build 10.0.20348.5622
Windows Server 2022 (Server Core installation), Windows Server 2022 - KB5124008 · fixed build 10.0.26100.9445, 10.0.26200.9445
Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 25H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems - KB5124012 · fixed build 10.0.28000.2954
Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems
What Microsoft changed
- September 8, 2026: Information published.
Details
- Weakness
- CWE-416: Use After Free
- Publicly disclosed (Microsoft)
- No
- Exploited (Microsoft)
- No
- Known exploited (CISA KEV)
- Not listed
- Published
- September 8, 2026
- Last revised
- September 8, 2026
Get told when this changes
Senserva Watch emails Microsoft security and patch alerts when something moves: a new exploitation report, a revised fix, a known issue. Free, one email address.
References
From Microsoft, CISA, NVD and FIRST data; the Microsoft details were read when this page was opened. Check the references above before you act.