CVE-2024-49138
CVE-2024-49138 is a security flaw in Microsoft Windows, Microsoft’s operating system for PCs and servers. Someone who already has a foothold can use Microsoft Windows to take full control of the machine. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 10 Dec 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 10.0.10240.20857, 10.0.14393.7606, 10.0.17763.6659 and 10.0.19044.5247 and others.
Description
CISA calls it a common log file system (CLFS) driver heap-based buffer overflow in Microsoft Windows. In its words: “Microsoft Windows Common Log File System (CLFS) driver contains a heap-based buffer overflow vulnerability that allows a local attacker to escalate privileges.”[1]
The underlying weakness is heap buffer overflow (CWE-122), in MITRE’s list of common software weaknesses.[2]
It scores 7.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, 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 10 Version 1507 | 10.0.10240.20857 |
| Windows 10 Version 1607 | 10.0.14393.7606 |
| Windows 10 Version 1809 | 10.0.17763.6659 |
| Windows 10 Version 21H2 | 10.0.19044.5247 |
| Windows 10 Version 22H2 | 10.0.19045.5247 |
| Windows 11 version 22H2 | 10.0.22621.4602 |
| Windows 11 version 22H3 | 10.0.22631.4602 |
| Windows 11 Version 23H2 | 10.0.22631.4602 |
Every device with Microsoft Windows needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 10 Dec 2024. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 31 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 26%. That’s in the top 3% 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 10.0.10240.20857 or later.Fixed in version 10.0.10240.20857, 10.0.14393.7606, 10.0.17763.6659 and 10.0.19044.5247 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 |
|---|---|
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.8.[2] | |
| 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 26%.[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 ·
Other heap buffer overflow flaws
- CVE-2026-94127, F5 BIG-IP APM: heap-based buffer overflow ·
- CVE-2025-25249, Fortinet products: heap-based buffer overflow ·
- CVE-2024-38812, VMware vCenter Server: heap-based buffer overflow ·
- CVE-2023-4911, GNU C Library: c library buffer overflow ·
- CVE-2023-27997, Fortinet FortiOS and FortiProxy SSL-VPN: heap-based buffer overflow ·
Every Microsoft flaw on CISA’s list · Everything added in December 2024
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Windows Common Log File System (CLFS) Driver Heap-Based Buffer Overflow Vulnerability”. Known Exploited Vulnerabilities Catalog, added 10 Dec 2024.
- ^ National Institute of Standards and Technology. “CVE-2024-49138 Detail”. National Vulnerability Database, published 12 Dec 2024.
- ^ Microsoft. Advisories and fixes: msrc.microsoft.com, msrc.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.262, percentile 98.0, 31 Oct 2026.
- CVE Program. “CVE-2024-49138”. 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.