What is the CVSS score of CVE-2026-33100?

CVE-2026-33100 has a CVSS 3.1 base score of 7.0 (High). CVSS vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of Microsoft are affected by CVE-2026-33100?

CVE-2026-33100 is a local privilege escalation in Windows AFD.sys affecting Windows 10, 11, and Server 2012-2025, allowing authenticated local users to gain SYSTEM-level control.. A patch is available.

How to fix or mitigate CVE-2026-33100?

Within 24 hours: inventory all Windows 10, 11, and Server 2012-2025 systems and confirm current patch levels via Microsoft Update or WSUS. Within 7 days: deploy vendor-released patches to all affected systems, prioritizing domain controllers, administrative workstations, and servers hosting sensitive data. Within 30 days: verify 100% patch deployment through security scanning tools and update configuration management baselines to enforce current patch levels.

Microsoft CVE-2026-33100

EUVD-2026-22623 HIGH

Use After Free (CWE-416)

2026-04-14 microsoft

GHSA-gjhf-vqgr-hxwj

Denial Of Service Use After Free Memory Corruption Microsoft

7.0

CVSS 3.1 · NVD

Temporal: 6.1

Severity by source

NVD PRIMARY

7.0 HIGH

AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CIRCL (temporal)

6.1 MEDIUM

cvss

Primary rating from NVD.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Local

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Re-analysis Queued

Apr 17, 2026 - 15:22 vuln.today

cvss_changed

Analysis Generated

Apr 14, 2026 - 19:36 vuln.today

EUVD ID Assigned

Apr 14, 2026 - 17:46 euvd

EUVD-2026-22623

Analysis Generated

Apr 14, 2026 - 17:46 vuln.today

Patch released

Apr 14, 2026 - 17:46 nvd

Patch available

CVE Published

Apr 14, 2026 - 16:58 nvd

HIGH 7.0

DescriptionCVE.org

Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

AnalysisAI

Local privilege escalation in Windows Ancillary Function Driver for WinSock (AFD.sys) affects all supported Windows 10, Windows 11, and Windows Server versions from 2012 through 2025. The CWE-416 use-after-free memory corruption flaw allows low-privileged authenticated attackers with local access to elevate to SYSTEM privileges, achieving complete control over confidentiality, integrity, and availability. SSVC framework rates this as non-automatable with total technical impact. No public exploit

Technical ContextAI

The Windows Ancillary Function Driver for WinSock (AFD.sys) is a kernel-mode component that provides socket support and network protocol handling for Windows Sockets (WinSock) API. This CWE-416 use-after-free vulnerability occurs when the driver improperly manages memory object lifecycle, allowing a reference to freed memory to be subsequently dereferenced. In kernel-mode drivers, use-after-free conditions are particularly dangerous because they enable attackers to control freed memory allocation and potentially redirect execution flow or manipulate kernel data structures. The affected CPE strings identify this as impacting the full spectrum of modern Windows operating systems including client editions (Windows 10 versions 1607/1809/21H2/22H2, Windows 11 versions 22H3/23H2/24H2/25H2/26H1) and server platforms (Windows Server 2012/2012 R2/2016/2019/2022/2025 including Server Core installations). The local attack vector (AV:L) combined with kernel-level driver vulnerability makes this a classic Windows privilege escalation primitive.

RemediationAI

Apply vendor-released security updates immediately through Windows Update or Microsoft Update Catalog. Patch to the following minimum versions: Windows Server 2012 to 6.2.9200.26026 or later, Windows Server 2012 R2 to 6.3.9600.23132 or later, Windows 10 Version 1607 and Server 2016 to 10.0.14393.9060 or later, Windows 10 Version 1809 and Server 2019 to 10.0.17763.8644 or later, Windows 10 Version 21H2 to 10.0.19044.7184 or later, Windows 10 Version 22H2 to 10.0.19045.7184 or later, Windows 11 versions 22H3/23H2 to 10.0.22631.6936 or later, Windows 11 Version 24H2 and Server 2025 to 10.0.26100.32690 or later, Windows 11 Version 25H2 to 10.0.26200.8246 or later, Windows 11 Version 26H1 to 10.0.28000.1836 or later, Windows Server 2022 to 10.0.20348.5020 or later, and Server 2022 23H2 Edition to 10.0.25398.2274 or later. Download patches from Microsoft Security Response Center at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33100. No effective workarounds exist for kernel-mode driver vulnerabilities beyond restricting local logon access to trusted users only. Prioritize patching systems with multiple local user accounts or those in shared/multi-tenant environments.