CVE-2024-43451
CVE-2024-43451 is a security flaw in Microsoft Windows, Microsoft’s operating system for PCs and servers. Attackers can make something fake look genuine in Microsoft Windows. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 12 Nov 2024.[1]
Microsoft Windows is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Fixed in version 10.0.26100.2314, 10.0.17763.6532, 10.0.20348.2849 and 10.0.19044.5131 and others.
Description
CISA calls it a nTLMv2 hash disclosure spoofing in Microsoft Windows. In its words: “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.”[1]
The underlying weakness is CWE-73, in MITRE’s list of common software weaknesses.[2]
It scores 6.5 out of 10 on the Common Vulnerability Scoring System, which rates it medium, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| Windows Server 2025 | 10.0.26100.2314 |
| Windows Server 2025 (Server Core installation) | 10.0.26100.2314 |
| Windows 10 Version 1809 | 10.0.17763.6532 |
| Windows Server 2019 | 10.0.17763.6532 |
| Windows Server 2019 (Server Core installation) | 10.0.17763.6532 |
| Windows Server 2022 | 10.0.20348.2849 |
| Windows 10 Version 21H2 | 10.0.19044.5131 |
| Windows 11 version 22H2 | 10.0.22621.4460 |
Every device with Microsoft Windows needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 12 Nov 2024, within a day of it being made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 3 Dec 2024 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 84%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Microsoft has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”[1]
- Update Microsoft Windows now.On Windows: Settings, Windows Update, Check for updates, then restart. Office updates come the same way, or from any Office app: File, Account, Update Options. Then turn on automatic updates, so the next fix arrives on its own.
- Check you’re on 10.0.26100.2314 or later.Fixed in version 10.0.26100.2314, 10.0.17763.6532, 10.0.20348.2849 and 10.0.19044.5131 and others. Anything older is what attackers are going after.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 6.5.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 84%.[4] |
See also
Other Microsoft Windows flaws
- CVE-2026-96951: command injection ·
- CVE-2026-85880: heap-based buffer overflow ·
- CVE-2026-81963: link following ·
- CVE-2008-4250: buffer overflow ·
- CVE-2026-32202: protection mechanism failure ·
- CVE-2025-60710: link following ·
Similar flaws
- CVE-2026-96656, Plex Media Server: external control of file name or path ·
- CVE-2025-0111, Palo Alto Networks PAN-OS: file read ·
Added the same day
- CVE-2024-49039, Microsoft Windows: task scheduler privilege escalation ·
- CVE-2021-41277, Metabase: geoJSON API local file inclusion ·
- CVE-2021-26086, Atlassian Jira Server and Data Center: path traversal ·
- CVE-2014-2120, Cisco Adaptive Security Appliance (ASA): cross-site scripting (XSS) ·
Every Microsoft flaw on CISA’s list · Everything added in November 2024
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Windows NTLMv2 Hash Disclosure Spoofing Vulnerability”. Known Exploited Vulnerabilities Catalog, added 12 Nov 2024.
- ^ National Institute of Standards and Technology. “CVE-2024-43451 Detail”. National Vulnerability Database, published 12 Nov 2024.
- ^ Microsoft. Advisories and fixes: msrc.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.843, percentile 99.7, 31 Oct 2026.
- CVE Program. “CVE-2024-43451”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.