CVE WatchSep 24, 2026

CVE-2025-21335

Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability

CVSS

7.8

High

EPSS

1.4%

p72

KEV

YES

Jan 14, 2025

Exploit Today

0-100

Published: Jan 14, 2025 · Last modified: Sep 24, 2026 · CWE-416

EPSS · 30d

1.4%EPSS · 30 days1.4%

2026-09-162026-10-14

KEV catalog record

Product

Microsoft / Windows

Vulnerability

Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability

Added to KEV

Jan 14, 2025

Remediate by

Feb 4, 2025

Known ransomware use

Summary description

Microsoft Windows Hyper-V NT Kernel Integration VSP contains a use-after-free vulnerability that allows a local attacker to gain SYSTEM privileges.

Required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Notes

https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-21335 ; https://nvd.nist.gov/vuln/detail/CVE-2025-21335

Technical description

Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-58099—

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———When copying knotes from a parent kqueue to a child, the copy code did not correctly exclude marker knotes (used internally to track list traversal position) before marking them as in-flux and releasing the kqueue lock. If another thread freed a marker while the lock was dropped, the subsequent in-flux decrement operated on freed memory. An unprivileged local user may be able to exploit these races to escalate privileges.8h CVE-2026-865678.8 HIG

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——0A flaw was found in DPDK lib/vhost. The VDUSE handler fails to invalidate vring pointers when the IOTLB is invalidated, leading to use-after-unmap.8h CVE-2026-1020785.9 MED

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——0A Use After Free vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). When web filtering for TCP traffic is configured, a high volume of DNS requests increases the likelihood of a flowd crash and restart, which leads to a complete service outage until the service has automatically recovered. This is a race condition outside the attacker's direct control. This issue affects Junos OS on SRX Series: * All versions before 23.2R2-S5; * from 23.4 before 23.4R2-S6; * from 24.2 before 24.2R2-S3; * from 24.4 before 24.4R2-S1; * from 25.2 before 25.2R1-S1, 25.2R2.7h CVE-2026-1019706.5 MED

—

——0A Use After Free vulnerability in the rpd PIM Join/Prune processing of Juniper Networks Junos OS and Junos OS Evolved platforms allows an unauthenticated adjacent attacker to crash the routing daemon via specific PIM messages when sparse mode PIM is configured.7h CVE-2026-972058.1 HIG

—

——0NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_core_module module. When asynchronous file I/O (AIO) is enabled in certain configurations, processing a Server Side Includes (SSI) page containing “include virtual” commands may trigger a Use-After-Free (UAF) in the NGINX worker process. This may cause memory corruption or a worker process crash. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system, corrupt its memory, or possibly trigger code execution. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.13h CVE-2026-84471—

—

——0The fix for CVE-2026-12996 was incomplete. A use-after-free in OpenVPN 2.6.0 through 2.6.22 and 2.7_alpha1 through 2.7.7 allows remote authenticated peers to potentially cause a denial of service or leak memory via crafted packets during TLS session promotion or expiry.1d