CVE-2024-43451 Microsoft Windows NTLMv2 Hash Disclosure Spoofing Vulnerability
Microsoft Windows contains an NTLMv2 hash spoofing vulnerability that could result in disclosing a user's NTLMv2 hash to an attacker via a file open operation. The attacker could then leverage this hash to impersonate that user.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 12 Nov 2024.
- Rated Medium severity (CVSS 6.5, scored by Vendor).
- Named in Cybergen threat actor reporting: DevMan.
- It has been in the catalogue for 724 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
NTLM Hash Disclosure Spoofing Vulnerability
Affected Versions
| Product | Versions |
|---|---|
| Microsoft Windows Server 2025 | 10.0.26100.0 to before 10.0.26100.2314 |
| Microsoft Windows Server 2025 (Server Core installation) | 10.0.26100.0 to before 10.0.26100.2314 |
| Microsoft Windows 10 Version 1809 | 10.0.17763.0 to before 10.0.17763.6532 |
| Microsoft Windows Server 2019 | 10.0.17763.0 to before 10.0.17763.6532 |
| Microsoft Windows Server 2019 (Server Core installation) | 10.0.17763.0 to before 10.0.17763.6532 |
| Microsoft Windows Server 2022 | 10.0.20348.0 to before 10.0.20348.2849 |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Microsoft Windows. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
Fix it
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vulnerability Management - 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
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