Windows CLFS driver use-after-free (CVE-2025-29824) — referring to a place already given up as though still usable
A use-after-free vulnerability in the Windows Common Log File System driver. An authorized party is described as able to elevate privileges locally, and use in ransomware campaigns is known.
Key facts
- CVE IDCVE-2025-29824
- Affected (vendor / product)Microsoft Windows
- CWECWE-416
- ExploitationListed in CISA KEV (exploitation confirmed); also confirmed used in ransomware
- Remediation due2025-04-29 (U.S. federal civilian agencies, BOD 22-01)
Key points
- The affected product is the Windows Common Log File System driver, classified as CWE-416, use after free.
- An authorized party is described as able to elevate privileges locally, and use in ransomware campaigns is known.
- Where a reference to released memory remains, it reads or writes there after the region has been put to another use.
- Privilege elevation presumes something already running inside, so it serves in widening a foothold rather than as an entrance.
- Added April 8, 2025 with a due date of April 29, 21 days later.
1The shape of use after free
A program reserves memory when it needs it and releases it when it does not. Released memory becomes available for another purpose. Where something still refers to a place already released, that reference reads or writes there after the region has been put to another use. That is the class called use after free.
- 1ReservingMemory is reserved as needed
- 2UsingThe region is read and written
- 3ReleasingNo longer needed, it is given up and may serve another purpose
- 4Where the flaw arisesWhere a reference to that place remains after it is given up
A remaining reference may cause no visible fault at first, because the released region may still hold its earlier contents until something else uses it. Trouble appears once it has been put to another use.
2Privilege elevation as the result
This one concerns local privilege elevation. Because it presumes having entered by some means, it is not on its own an initial entrance. It may instead serve in moving from limited privilege to something wider. That use in ransomware campaigns is known reads as reflecting that this stage sits within how attacks actually proceed.
3A logging mechanism as the target
The target is part of a mechanism for handling records. Mechanisms of this kind run constantly regardless of what a user does, and often execute with high privilege. The records this site holds include other entries for the same mechanism, likewise concerning privilege elevation.
4Thinking in stages
Attacks rarely complete through a single vulnerability. They divide into entering, widening privilege and achieving an objective. This one sits at the second stage. This site also covers vulnerabilities reachable without authentication and vulnerabilities used in combination, from which it emerges that different classes of flaw serve at different stages.
Why it matters
Attacks divide into entering, widening privilege and achieving an objective, with different classes of flaw at each stage. Boundary defences cannot address the classes that operate after the boundary is passed.
FAQ
What is use after free?
Where does local privilege elevation fit?
Sources (primary)
This article is an independent organization based on the U.S. official data below. Always verify the exact, latest details and applicability with the official and vendor sources.
- CISA KEV Catalog (known exploited list)
- NVD (CVE details / CVSS)
- Vendor / reference advisory
- This product uses data from the NVD API but is not endorsed or certified by the NVD. KEV data is CC0 (public domain).