Remote code execution in Microsoft SPNEGO Extended Negotiation (NEGOEX) Security Mechanism

1) Use-after-free

EUVDB-ID: #VU102802

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 - Use After Free

Exploit availability: No

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: 10 21H2 10.0.19041.3920 - 11 24H2 10.0.26100.2894

Windows Server: 2008 R2 SP1 - 2025 10.0.26100.2605

CPE2.3

• cpe:2.3:o:microsoft:windows:10_21H2:10.0.19044.5247:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_22H2:10.0.19045.5247:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_1507:10.0.10240.20857:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_1607:10.0.14393.7606:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:10_1809:10.0.17763.6659:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:11_22H2:10.0.22621.4602:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:11_23H2:10.0.22631.4602:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows:11_24H2:10.0.26100.2894:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server:2008_R2:6.1.7601.27467:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server:2012:6.2.9200.25222:*:*:*:*:*:*

External links

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

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.