Heap Buffer Overflow in Windows Win32K Enables Local Privilege Escalation
CVSS 3.1
7.8high
EPSS
<1%p31
Published
()
Modified
AI analysis
CVE-2026-62712 is a heap-based buffer overflow (CWE-122) in the Windows Win32K kernel component, with Microsoft's related advisories (ZDI-26-542/618/619/620/621) tying the flaw to user-mode printer driver (UMPD) graphics callbacks such as UMPDDrvBitBlt, UMPDDrvStretchBlt and UMPDDrvRealizeBrush. A local attacker with valid low-privileged credentials can trigger the overflow through crafted GDI/printer-driver operations, with no user interaction required. Successful exploitation elevates the attacker from a standard user to kernel/SYSTEM level, yielding high confidentiality, integrity and availability impact on the host. Every Windows 10 (1607, 1809, 21H2, 22H2), Windows 11 (23H2 through 26H1) and Windows Server (2012, 2016, 2019, 2022) installation on the listed builds is affected, which spans most of the supported Windows fleet. There is no public proof-of-concept, no CISA KEV listing, and a low EPSS of 0.4%, indicating no confirmed exploitation to date.
What to do: Apply the patch for CVE-2026-62712 from Microsoft's security update on all listed Windows 10, Windows 11 and Windows Server builds, prioritizing multi-user systems such as RDS hosts and print servers where untrusted users can execute code. Until patched, restrict interactive logon rights on servers to trusted users, since a kernel win32k overflow of this type has no reliable workaround. Verify remediation against the build numbers listed in Microsoft's advisory rather than assuming a single KB applies to every branch.
Affected
Microsoft Windows 10
1607, 1809, 21H2, 22H2
Microsoft Windows 11
23H2, 24H2, 25H2, 26H1
Microsoft Windows Server
2012, 2016, 2019, 2022
Estimated exposure
mass≈1 billion+ Windows installations (every unpatched install of the listed Windows 10/11/Server builds is affected) — Public estimates put the active Windows 10/11 device base on the order of 1.4 billion, with Windows Server deployed in millions of instances, and the affected version list covers nearly all currently supported Windows SKUs.
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description
Heap-based buffer overflow in Windows Win32K allows an authorized attacker to elevate privileges locally.
windows 10 1607, windows 10 1809, windows 10 21h2, windows 10 22h2, windows 11 23h2, windows 11 24h2, windows 11 25h2, windows 11 26h1, windows server 2012, windows server 2016, windows server 2019, windows server 2022
ZDI disclosed CVE-2026-62712, a CVSS 7.8 Windows UMPDDrvStretchBlt improper object-management flaw enabling local privilege escalation.
Zero Day Initiative advisory ZDI-26-618 describes an improper object management issue in Microsoft Windows' UMPDDrvStretchBlt component. A local attacker who can already execute low-privileged code on the system can escalate privileges. The flaw carries a CVSS 3.0 rating of 7.8; details on affected versions and patch availability are limited in the advisory.
ZDI disclosed CVE-2026-62712, a CVSS 7.8 Windows UMPDDrvPlgBlt improper object-management flaw enabling local privilege escalation.
Zero Day Initiative advisory ZDI-26-620 describes an improper object management flaw in Microsoft Windows' UMPDDrvPlgBlt component, sharing CVE-2026-62712 with the related UMPDDrvStretchBlt advisory. A local attacker able to run low-privileged code can escalate privileges on affected installations. The issue carries a CVSS 3.0 rating of 7.8.
ZDI discloses CVE-2026-62712, a CVSS 7.8 Windows UMPDDrvBitBlt improper object management flaw allowing local attackers to escalate privileges.
ZDI advisory ZDI-26-542 describes improper object management in Microsoft Windows' UMPDDrvBitBlt function, tracked as CVE-2026-62712 with a CVSS score of 7.8. The flaw allows local attackers to escalate privileges on affected Windows installations. Exploitation requires first obtaining the ability to execute low-privileged code on the target system.
ZDI disclosed CVE-2026-62712, a CVSS 7.8 improper object management flaw in Windows UMPDDrvRealizeBrush enabling local privilege escalation after low-privileged code execution.
The Zero Day Initiative published ZDI-26-621 covering a local privilege escalation vulnerability in Microsoft Windows' UMPDDrvRealizeBrush component, caused by improper object management. An attacker must already be able to execute low-privileged code on the target system before exploiting the flaw. ZDI assigned the vulnerability a CVSS score of 7.8 and the CVE identifier CVE-2026-62712.
ZDI disclosed CVE-2026-62712, a CVSS 7.8 improper object management flaw in Windows UMPDDrvStretchBltROP enabling local privilege escalation from low-privileged code.
The Zero Day Initiative published ZDI-26-619 covering a local privilege escalation vulnerability in Microsoft Windows' UMPDDrvStretchBltROP function, stemming from improper object management. Exploitation requires that the attacker first obtain the ability to run low-privileged code on the target system. ZDI rated the issue CVSS 7.8 and assigned CVE-2026-62712, the same identifier listed in the companion UMPDDrvRealizeBrush advisory.