OnlyPatch
Windows USB Print Driver

CVE-2026-32223 — Windows USB Printing Stack (usbprint.sys) Elevation of Privilege Vulnerability

Important CVSS 6.8 EPSS 0.00522 🔬 Patch diffed 2026-04 archive

Executive Summary

Heap-based buffer overflow in Windows USB Print Driver allows an unauthorized attacker to elevate privileges with a physical attack.

Overview

6.8
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Elevation of Privilege
Weakness CWE-122: Heap-based Buffer Overflow
Released Apr 14 2026
Last Updated Apr 14 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00522 — 0.41749 percentile
NVD CVSS 6.8 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Physical
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 5.9

EPSS Score

0.00522
probability of exploitation in the next 30 days
0.41749 percentile - updated 2026-08-14
View on FIRST.org

Affected Products

8 affected products
Product KB Article Severity Impact Restart Required
Windows 11 Version 24H2 for ARM64-based Systems 5083769 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 24H2 for x64-based Systems 5083769 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 25H2 for ARM64-based Systems 5083769 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 25H2 for x64-based Systems 5083769 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 26H1 for ARM64-based Systems 5083768 (Security Update) Important Elevation of Privilege Yes
Windows 11 version 26H1 for x64-based Systems 5083768 (Security Update) Important Elevation of Privilege Yes
Windows Server 2025 5082063 (Security Update) Important Elevation of Privilege Yes
Windows Server 2025 (Server Core installation) 5082063 (Security Update) Important Elevation of Privilege Yes

Patches

3 patches
Article Type Restart
5083769 Security Update Yes
5083768 Security Update Yes
5082063 Security Update Yes

Patch Diff

ghidriff · usbprint.sys (KB5082063)

Heap buffer overflow in Windows USB printer driver (usbprint.sys). When processing IOCTL 0x220064, Make1284IdStringFromUsbStrings concatenates MFG and MDL USB string descriptors into a buffer whose size is determined by OutputBufferLength. The copy size can exceed the destination buffer, causing a controlled heap overflow in NonPagedPoolNx.

Pre-patch version 10.0.26100.7920
Post-patch version 10.0.26100.8246
Function Address Change Note
USBPRINT_ProcessIOCTL modified Added validation of OutputBufferLength before processing IOCTL 0x220064
Make1284IdStringFromUsbStrings modified Added bounds check to ensure MFG+MDL concatenation does not exceed destination buffer
View full diff report View RCA report Download PoC

Attack Path

Heap overflow from concatenating USB device strings into a buffer sized by the caller's output length

Attack path for CVE-2026-32223 Heap overflow from concatenating USB device strings into a buffer sized by the caller's output length 01 — ENTRY Attacker plugs in a USB device, or drives the printer IOCTL locally IOCTL 0x220064 to usbprint.sys. The MFG and MDL strings come from the device's own USB string descriptors, so a malicious or emulated device controls them. 02 — CONTROLLED INPUT MFG and MDL descriptor contents and lengths are device-controlled Combined length is unrelated to the destination the driver picked. 03 — PATH Make1284IdStringFromUsbStrings builds the IEEE-1284 ID string The destination buffer size is derived from OutputBufferLength supplied with the IOCTL. 04 — MISSING CHECK The concatenation length is never checked against the destination size MFG + MDL can exceed the allocation. The patch validates OutputBufferLength in USBPRINT_ProcessIOCTL and adds a bounds check inside Make1284IdStringFromUsbStrings. 05 — PRIMITIVE Controlled heap overflow in NonPagedPoolNx Content comes from the device descriptors, so both length and bytes are attacker-chosen.

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

Jongseong Kim (nevul37) working with ENKI Whitehat
hao huang
Thanatos Tian & @2st__ with Diffract & Zhiniang Peng with HUST
Dongjun Kim (smiljun), working with ENKI WhiteHat
Donghyeon Oh
Jonghoi Kim

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