Security Digest · Vulnerability record · Known exploited
CVE-2024-43451: Microsoft Windows NTLMv2 Hash Disclosure Spoofing Vulnerability
Exploited in the wild (CISA KEV). NTLM Hash Disclosure Spoofing Vulnerability
CISA KEV · added 2024-11-12 CVSS 6.5 Medium EPSS 84.3% · p99.7
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run Microsoft Windows. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-11-12, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-12-03; treat that as the outer limit, not the target.
- EPSS 84.3%, percentile 99.7: FIRST’s model estimates a 84.3% chance of exploitation activity in the next 30 days, higher than 99.7% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
What it is
NTLM Hash Disclosure Spoofing Vulnerability
CISA’s summary
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.
Weakness type: CWE-73.
Product: Microsoft Windows · Assigned by: microsoft · Published: 2024-11-12
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Microsoft | Windows Server 2025 | 10.0.26100.0 < 10.0.26100.2314 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 < 10.0.26100.2314 |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 < 10.0.17763.6532 |
| Microsoft | Windows Server 2019 | 10.0.17763.0 < 10.0.17763.6532 |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 < 10.0.17763.6532 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 < 10.0.20348.2849 |
| Microsoft | Windows 10 Version 21H2 | 10.0.19043.0 < 10.0.19044.5131 |
| Microsoft | Windows 11 version 22H2 | 10.0.22621.0 < 10.0.22621.4460 |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 < 10.0.19045.5131 |
| Microsoft | Windows 11 version 22H3 | 10.0.22631.0 < 10.0.22631.4460 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoft | 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:F/RL:O/RC:C |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: required (a user must click/open something)
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2024-11-12; federal due date 2024-12-03. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active, automatable no, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 84.27% probability of exploitation activity in the next 30 days; percentile 99.7.
Timeline
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CVE record published by microsoft
- — CISA remediation deadline for US federal agencies
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- NTLM Hash Disclosure Spoofing Vulnerability msrc.microsoft.com
Vulnerability records
- CVE.org record CVE-2024-43451 cve.org
- NVD entry CVE-2024-43451 nvd.nist.gov
Government
All exploited Microsoft vulnerabilities · Today’s Security Digest