OnlyPatch
Windows Kernel

CVE-2026-50475 — Windows Kernel Information Disclosure Vulnerability

Important CVSS 5.5 EPSS 0.00536 🔬 Patch diffed 2026-07 archive

Executive Summary

Buffer over-read in Windows Kernel allows an authorized attacker to disclose information locally.

Overview

5.5
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
More Likely
MS Exploit Likelihood
Category Information Disclosure
Weakness CWE-126: Buffer Over-read
Released Jul 14 2026
Last Updated Jul 14 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00536 — 0.42528 percentile
NVD CVSS 5.5 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
None
AVAILABILITY
None
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 4.8

EPSS Score

0.00536
probability of exploitation in the next 30 days
0.42528 percentile - updated 2026-08-14
View on FIRST.org

Affected Products

27 affected products
Product KB Article Severity Impact Restart Required
Windows 10 Version 1607 for 32-bit Systems 5099535 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1607 for x64-based Systems 5099535 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1809 for 32-bit Systems 5099538 (Security Update) Important Information Disclosure Yes
Windows 10 Version 1809 for x64-based Systems 5099538 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H2 for 32-bit Systems 5099539 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H2 for ARM64-based Systems 5099539 (Security Update) Important Information Disclosure Yes
Windows 10 Version 21H2 for x64-based Systems 5099539 (Security Update) Important Information Disclosure Yes
Windows 10 Version 22H2 for 32-bit Systems 5099539 (Security Update) Important Information Disclosure Yes
Windows 10 Version 22H2 for ARM64-based Systems 5099539 (Security Update) Important Information Disclosure Yes
Windows 10 Version 22H2 for x64-based Systems 5099539 (Security Update) Important Information Disclosure Yes
Windows 11 Version 24H2 for ARM64-based Systems 5101650 (Security Update) Important Information Disclosure Yes
Windows 11 Version 24H2 for x64-based Systems 5101650 (Security Update) Important Information Disclosure Yes
Windows 11 Version 25H2 for ARM64-based Systems 5101650 (Security Update) Important Information Disclosure Yes
Windows 11 Version 25H2 for x64-based Systems 5101650 (Security Update) Important Information Disclosure Yes
Windows 11 Version 26H1 for ARM64-based Systems 5101649 (Security Update) Important Information Disclosure Yes
Windows 11 version 26H1 for x64-based Systems 5095051 (Security Update) Important Information Disclosure Yes
Windows Server 2012 5099445 (Monthly Rollup) Important Information Disclosure Yes
Windows Server 2012 (Server Core installation) 5099445 (Monthly Rollup) Important Information Disclosure Yes
Windows Server 2012 R2 5099444 (Monthly Rollup) Important Information Disclosure Yes
Windows Server 2012 R2 (Server Core installation) 5099444 (Monthly Rollup) Important Information Disclosure Yes
Windows Server 2016 5099535 (Security Update) Important Information Disclosure Yes
Windows Server 2016 (Server Core installation) 5099535 (Security Update) Important Information Disclosure Yes
Windows Server 2019 5099538 (Security Update) Important Information Disclosure Yes
Windows Server 2019 (Server Core installation) 5099538 (Security Update) Important Information Disclosure Yes
Windows Server 2022 5099540 (Security Update) Important Information Disclosure Yes
Windows Server 2025 5099536 (Security Update) Important Information Disclosure Yes
Windows Server 2025 (Server Core installation) 5099536 (Security Update) Important Information Disclosure Yes

Patches

10 patches
Article Type Restart
5099535 Security Update Yes
5099538 Security Update Yes
5099539 Security Update Yes
5101650 Security Update Yes
5101649 Security Update Yes
5095051 Security Update Yes
5099445 Monthly Rollup Yes
5099444 Monthly Rollup Yes
5099540 Security Update Yes
5099536 Security Update Yes

Patch Diff

ghidriff · netio.sys (KB5101650)

Off-by-one bounds check in NsipGetAllInformationProviderParameters. Uses <= instead of < when comparing user-supplied TableIndex against maxVtableIndex, allowing a read of 0x10 bytes past the vtable array. Leaks tcpip.sys kernel addresses via IOCTL 0x120007 to \Device\Nsi, defeating KASLR.

Pre-patch version 10.0.26100.8737 Download
Post-patch version 10.0.26100.8875 Download
Function Address Change Note
NsipGetAllInformationProviderParameters 1400638a0 code Off-by-one fix — bounds check changed from <= to <
View full diff report View RCA report Download PoC

Attack Path

KASLR defeat - an off-by-one bounds check reads one vtable entry past the end of the array

Attack path for CVE-2026-50475 KASLR defeat - an off-by-one bounds check reads one vtable entry past the end of the array 01 — ENTRY Any standard user opens \Device\Nsi and issues the NSI query IOCTL DeviceIoControl with IOCTL 0x120007. The Network Store Interface device is reachable without elevation. 02 — CONTROLLED INPUT TableIndex in the request selects which provider vtable entry to read The index is taken straight from the user-supplied request buffer. 03 — PATH NsipGetAllInformationProviderParameters validates the index and indexes the array The handler compares TableIndex against maxVtableIndex before using it as an array subscript. 04 — MISSING CHECK The comparison uses <= where it should use < TableIndex == maxVtableIndex passes validation and indexes one element past the end of the vtable array. The patch changes the operator to <. 05 — PRIMITIVE 0x10 bytes of adjacent kernel memory returned to the caller The out-of-bounds entry contains tcpip.sys pointers, which are copied back to user mode. Information disclosure only - it defeats KASLR and pairs with a separate write primitive for EoP.

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

grass341
KPC with Cisco Talos

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