pNFS: Fix uninited ptr deref in block/scsi layout

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-38691
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-09-04 16:15:37 UTC
Updated2026-05-12 13:16:55 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-908

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 579b85f893d9885162e1cabf99a4a088916e143e git Not specified
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 2896f101110076ac6bf99d7aaf463d61e26f89dd git Not specified
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 4f783333cbfa2ee7d4aa8e47f6bd1b3f77534fcf git Not specified
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 9be5c04beca3202d0a5f09fb4b2ecb644caa0bc5 git Not specified
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 24334f3cf8a294f253071b5bf22d754dbb6d0f2d git Not specified
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 f0b2eee3fbba9b7e3746ef698424ef5e4a197776 git Not specified
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 94ec6d939031a616474376dadbf4a8d0ef8b0bcc git Not specified
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 37c3443a2685528f972d910a6fb87716b96fef46 git Not specified
CNA Linux Linux affected 34dc93c2fc04da0d01acf8a1660b4ab276208af7 9768797c219326699778fba9cd3b607b2f1e7950 git Not specified
CNA Linux Linux affected 3.18 Not specified
CNA Linux Linux unaffected 3.18 semver Not specified
CNA Linux Linux unaffected 5.4.297 5.4.* semver Not specified
CNA Linux Linux unaffected 5.10.241 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.190 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.149 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.103 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.43 6.12.* semver Not specified
CNA Linux Linux unaffected 6.15.11 6.15.* semver Not specified
CNA Linux Linux unaffected 6.16.2 6.16.* semver Not specified
CNA Linux Linux unaffected 6.17 * original_commit_for_fix Not specified
ADP Siemens SIMATIC CN 4100 affected V5.0 custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified

References

ReferenceSourceLinkTags
lists.debian.org/debian-lts-announce/2025/10/msg00008.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Third Party Advisory
git.kernel.org/stable/c/9768797c219326699778fba9cd3b607b2f1e7950 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-082556.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/94ec6d939031a616474376dadbf4a8d0ef8b0bcc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/579b85f893d9885162e1cabf99a4a088916e143e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/2896f101110076ac6bf99d7aaf463d61e26f89dd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/24334f3cf8a294f253071b5bf22d754dbb6d0f2d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-032379.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/37c3443a2685528f972d910a6fb87716b96fef46 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/f0b2eee3fbba9b7e3746ef698424ef5e4a197776 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/4f783333cbfa2ee7d4aa8e47f6bd1b3f77534fcf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/9be5c04beca3202d0a5f09fb4b2ecb644caa0bc5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
lists.debian.org/debian-lts-announce/2025/10/msg00007.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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