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High MSRC-CVE-2026-121680 1 CVE

Windows NTLM Spoofing Vulnerability

Published Nov 10, 2026 · Updated Nov 13, 2026 · Revision 2

Summary

Impact: Spoofing. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of confidentiality (C:H). What does that mean for this vulnerability?
This vulnerability discloses a user's NTLMv2 hash to the attacker who could use this to authenticate as the user.

How could an attacker exploit this vulnerability?
External attackers could send specially crafted emails that will cause a connection from the victim to an untrusted location of attackers' control. This will leak the Net-NTLMv2 hash of the victim to the untrusted network which an attacker can then relay to another service and authenticate as the victim.

Security updates
16.0.20625.20014 — https://support.microsoft.com/en-us/microsoft-365
10.0.14393.9688 — https://support.microsoft.com/help/5131291
10.0.17763.9487 — https://support.microsoft.com/help/5131085
10.0.19044.7846 — https://support.microsoft.com/help/5131096
10.0.20348.5870 — https://support.microsoft.com/help/5131090
10.0.22631.7711 — https://support.microsoft.com/help/5131087
10.0.26100.9974 — https://support.microsoft.com/help/5132061
10.0.26100.9911 — https://support.microsoft.com/help/5132043
10.0.26100.33822 — https://support.microsoft.com/help/5131080
10.0.26100.33730 — https://support.microsoft.com/help/5131077
10.0.28000.3501 — https://support.microsoft.com/help/5132059

Vulnerabilities 1

Revision history

  1. #2

    Added Microsoft Office software to the Security Updates table. Customers that are running supported version of Microsoft Office are encouraged to update to the indicated version to be protected from this vulnerability.

  2. #1

    Information published.

References