U.S. flag   An official website of the United States government
Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock (Dot gov) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

CVE-2025-38691 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: pNFS: Fix uninited ptr deref in block/scsi layout The error occurs on the third attempt to encode extents. When function ext_tree_prepare_commit() reallocates a larger buffer to retry encoding extents, the "layoutupdate_pages" page array is initialized only after the retry loop. But ext_tree_free_commitdata() is called on every iteration and tries to put pages in the array, thus dereferencing uninitialized pointers. An additional problem is that there is no limit on the maximum possible buffer_size. When there are too many extents, the client may create a layoutcommit that is larger than the maximum possible RPC size accepted by the server. During testing, we observed two typical scenarios. First, one memory page for extents is enough when we work with small files, append data to the end of the file, or preallocate extents before writing. But when we fill a new large file without preallocating, the number of extents can be huge, and counting the number of written extents in ext_tree_encode_commit() does not help much. Since this number increases even more between unlocking and locking of ext_tree, the reallocated buffer may not be large enough again and again.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to [email protected].

URL Source(s) Tag(s)
https://git.kernel.org/stable/c/24334f3cf8a294f253071b5bf22d754dbb6d0f2d kernel.org
https://git.kernel.org/stable/c/2896f101110076ac6bf99d7aaf463d61e26f89dd kernel.org
https://git.kernel.org/stable/c/37c3443a2685528f972d910a6fb87716b96fef46 kernel.org
https://git.kernel.org/stable/c/4f783333cbfa2ee7d4aa8e47f6bd1b3f77534fcf kernel.org
https://git.kernel.org/stable/c/579b85f893d9885162e1cabf99a4a088916e143e kernel.org
https://git.kernel.org/stable/c/94ec6d939031a616474376dadbf4a8d0ef8b0bcc kernel.org
https://git.kernel.org/stable/c/9768797c219326699778fba9cd3b607b2f1e7950 kernel.org
https://git.kernel.org/stable/c/9be5c04beca3202d0a5f09fb4b2ecb644caa0bc5 kernel.org
https://git.kernel.org/stable/c/f0b2eee3fbba9b7e3746ef698424ef5e4a197776 kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-38691
NVD Published Date:
09/04/2025
NVD Last Modified:
09/05/2025
Source:
kernel.org