SYSTEM privilege escalation via WMI size underflow
Published Jun 9, 2026 · Updated Jun 9, 2026
Integer underflow in the Windows NT OS Kernel allows local users to elevate privileges to SYSTEM through a crafted WMI request. The WMI serialization path subtracts an aligned record size from an unaligned size, wrapping the counter and writing the next WNODE item beyond the kernel SystemBuffer. A locally authenticated low-privilege account can reach the path without user interaction and use the out-of-bounds write to obtain SYSTEM control.
Summary
What happened
Integer underflow in the Windows NT OS Kernel allows local users to elevate privileges to SYSTEM through a crafted WMI request. The WMI serialization path subtracts an aligned record size from an unaligned size, wrapping the counter and writing the next WNODE item beyond the kernel SystemBuffer. A locally authenticated low-privilege account can reach the path without user interaction and use the out-of-bounds write to obtain SYSTEM control.
The record
- CVE
- CVE-2026-42980
- Published
- Jun 9, 2026
- Updated
- Jun 9, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-122, CWE-191, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 9, 2026CVE publishedPublication date reported by the CVE source.
- Jun 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.8880
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- CVE-2026-42980 Public Exploit and Researchfunctional · demonstrated
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Technologies
Your stack
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Your stack
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