#VU102802 Use-after-free in Windows and Windows Server - CVE-2025-21295

Vulnerability identifier: #VU102802

Vulnerability risk: High

CVSSv4.0: 7.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2025-21295

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Windows
Operating systems & Components / Operating system
Windows Server
Operating systems & Components / Operating system

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error in SPNEGO Extended Negotiation (NEGOEX) Security Mechanism. A remote attacker can execute arbitrary code on the target sytem.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: before 10 21H2, 10 22H2, 10 1507, 10 1607, 10 1809, 11 22H2, 11 23H2, 11 24H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2

Windows Server: before 2008 R2, 2012 R2, 2012, 2022 23H2, 2022, 2025, 2008 R2, 2008 R2, 2008 R2, 2008 R2

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External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21295

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.