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Windows NT OS Kernel

CVE-2026-42980 — NT OS Kernel Elevation of Privilege Vulnerability

Important CVSS 7.8 EPSS 0.06949 🔬 Patch diffed 2026-06 archive

Executive Summary

Integer underflow (wrap or wraparound) in Windows NT OS Kernel allows an authorized attacker to elevate privileges locally.

Overview

7.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
Category Elevation of Privilege
Weakness CWE-191: Integer Underflow (Wrap or Wraparound)
Released Jun 9 2026
Last Updated Jun 9 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.06949 — 0.93533 percentile
NVD CVSS 7.8 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 6.8

EPSS Score

0.06949
probability of exploitation in the next 30 days
0.93533 percentile - updated 2026-08-14
View on FIRST.org

Affected Products

30 affected products
Product KB Article Severity Impact Restart Required
Windows 10 Version 1607 for 32-bit Systems 5094122 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1607 for x64-based Systems 5094122 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1809 for 32-bit Systems 5094123 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1809 for x64-based Systems 5094123 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for 32-bit Systems 5094127 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for ARM64-based Systems 5094127 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for x64-based Systems 5094127 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for 32-bit Systems 5094127 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for ARM64-based Systems 5094127 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for x64-based Systems 5094127 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 23H2 for ARM64-based Systems 5093998 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 23H2 for x64-based Systems 5093998 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 24H2 for ARM64-based Systems 5094126 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 24H2 for x64-based Systems 5094126 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 25H2 for ARM64-based Systems 5094126 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 25H2 for x64-based Systems 5094126 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 26H1 for ARM64-based Systems 5095051 (Security Update) Important Elevation of Privilege Yes
Windows 11 version 26H1 for x64-based Systems 5095051 (Security Update) Important Elevation of Privilege Yes
Windows Server 2012 5094042 (Monthly Rollup) Important Elevation of Privilege Yes
Windows Server 2012 (Server Core installation) 5094042 (Monthly Rollup) Important Elevation of Privilege Yes
Windows Server 2012 R2 5094041 (Monthly Rollup) Important Elevation of Privilege Yes
Windows Server 2012 R2 (Server Core installation) 5094041 (Monthly Rollup) Important Elevation of Privilege Yes
Windows Server 2016 5094122 (Security Update) Important Elevation of Privilege Yes
Windows Server 2016 (Server Core installation) 5094122 (Security Update) Important Elevation of Privilege Yes
Windows Server 2019 5094123 (Security Update) Important Elevation of Privilege Yes
Windows Server 2019 (Server Core installation) 5094123 (Security Update) Important Elevation of Privilege Yes
Windows Server 2022 5094128 (Security Update) Important Elevation of Privilege Yes
Windows Server 2022 (Server Core installation) 5094128 (Security Update) Important Elevation of Privilege Yes
Windows Server 2025 5094125 (Security Update) Important Elevation of Privilege Yes
Windows Server 2025 (Server Core installation) 5094125 (Security Update) Important Elevation of Privilege Yes

Patches

10 patches
Article Type Restart
5094122 Security Update Yes
5094123 Security Update Yes
5094127 Security Update Yes
5093998 Security Update Yes
5094126 Security Update Yes
5095051 Security Update Yes
5094042 Monthly Rollup Yes
5094041 Monthly Rollup Yes
5094128 Security Update Yes
5094125 Security Update Yes

Patch Diff

ghidriff + GhidraMCP verification · ntoskrnl.exe (KB5101650)

WMI integer underflow (CWE-191 -> CWE-787): nt!WmipQueryAllDataMultiple (IOCTL 0x22812C) and nt!WmipQuerySingleMultiple (IOCTL 0x228130) subtract an 8-aligned provider-reported size from a 32-bit remaining-output counter without checking it fits. A WMI instance whose serialized size R is not 8-aligned (slop) passes the requiredSize=(DataSize+73)&~7 gate yet wraps the counter (R - ALIGN8(R)); the next WNODE item is then serialized out of bounds past the kernel SystemBuffer, giving a controlled OOB write (used by the public G4sp4rCS exploit to corrupt sprayed npfs data queue entries -> arbitrary read -> SYSTEM token). VERIFIED 2026-07-20: the saturating-subtract fix ships in BOTH builds behind WIL flag Feature_1045423416; KB5101650 is a CFR flag enablement, not a code change — ghidriff shows 0 changes in the WMI path (70,713/70,714 functions matched, 6 unrelated churn).

Pre-patch version 10.0.26100.8737 Download
Post-patch version 10.0.26100.8875 Download
Function Address Change Note
nt!WmipQuerySingleMultiple 0x1407a4fc0 (pre-patch); vulnerable sub @ +0x401 none (code identical in both builds) — fix enabled via Feature_1045423416 flag flip IOCTL 0x228130 path; outRemaining -= alignedActualSize underflow; saturating subtract already compiled in pre-patch, dormant behind CFR flag. Verified via GhidraMCP decompilation of 10.0.26100.8737.
nt!WmipQueryAllDataMultiple vulnerable sub @ +0x29a none (code identical in both builds) — fix enabled via Feature_1045423416 flag flip IOCTL 0x22812C path; same unchecked aligned-size subtraction; same flag-gated saturating pattern present pre-patch. Verified via GhidraMCP.
Feature_1045423416__private_IsEnabledDeviceUsageNoInline / _IsEnabledFallback 0x14064a9d4 / 0x14064aa0c (pre-patch) present in both builds; flag STATE changed by KB5101650 (CFR enablement, data-side) CFR kill-switch gating both saturating subtractions; state lives in servicing/rollout data outside function-diff scope
Unrelated churn (6 code-changed) code RtlpCheckFunctionPatchAppliedInOriginalImage, FsRtlpRequestShareableOplock, FsRtlpComputeShareableOplockState, SepSecureBootCorrectBcd, NtFilterBootOption, RtlpHpVsSlotCreate; 1 added: Feature_3244801339__private_IsEnabledFallback
View full diff report View RCA report Download PoC

Attack Path

WMI integer underflow to controlled out-of-bounds write in the kernel output buffer - fix present but CFR-gated in both builds

Attack path for CVE-2026-42980 WMI integer underflow to controlled out-of-bounds write in the kernel output buffer - fix present but CFR-gated in both builds 01 — ENTRY Any standard user issues a WMI multiple-query IOCTL IOCTL 0x22812C (WmipQueryAllDataMultiple) or 0x228130 (WmipQuerySingleMultiple) against the WMI device. No elevation required. 02 — CONTROLLED INPUT A WMI instance whose serialized size R is not 8-aligned The attacker picks a provider and instance so that R has slop below the 8-byte alignment boundary. 03 — PATH The handler admits the request, then decrements the remaining-output counter requiredSize = (DataSize + 73) & ~7 passes the admission gate, after which the code performs outRemaining -= ALIGN8(R) on a 32-bit counter. 04 — MISSING CHECK The aligned size can exceed the true remaining count, and the subtraction is unchecked R - ALIGN8(R) wraps the 32-bit counter to a huge value, so the serializer believes it has almost unlimited room left in the kernel SystemBuffer. 05 — PRIMITIVE The next WNODE item is serialized past the end of the SystemBuffer Controlled out-of-bounds write. The public G4sp4rCS exploit corrupts sprayed npfs data queue entries to build an arbitrary read and swap the process token to SYSTEM. 06 — MISSING CHECK The saturating-subtract fix is compiled into BOTH builds behind Feature_1045423416 Verified by decompilation of 10.0.26100.8737: the corrected arithmetic was already present pre-patch but dormant, gated by a Controlled Feature Rollout flag. The August build does not add the code - it enables it. Patch state therefore cannot be inferred from file version alone.

Derived from the patch delta: the checks added by the vendor identify which fields crossed a trust boundary unvalidated. Reachability and privilege are taken from the call chain in the RCA report.

Known Exploits

Acknowledgments

Anonymous

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