nfsd: fix NULL dereference in nfs3svc_encode_getaclres

Summary

CVECVE-2021-47316
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2024-05-21 15:15:18 UTC
Updated2026-05-12 10:16:37 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: nfsd: fix NULL dereference in nfs3svc_encode_getaclres In error cases the dentry may be NULL. Before 20798dfe249a, the encoder also checked dentry and d_really_is_positive(dentry), but that looks like overkill to me--zero status should be enough to guarantee a positive dentry. This isn't the first time we've seen an error-case NULL dereference hidden in the initialization of a local variable in an xdr encoder. But I went back through the other recent rewrites and didn't spot any similar bugs.

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

EPSS: 0.000550000 probability, percentile 0.171670000 (date 2026-05-12)

Problem Types: CWE-476

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 d505e66191072748620fc0af038cea4e4da0e3cd e79057d15d96ef19de4de6d7e479bae3d58a2a8d git Not specified
CNA Linux Linux affected 20798dfe249a01ad1b12eec7dbc572db5003244a 650e6f383a6eb40f7c0a010982a74ab4b6893870 git Not specified
CNA Linux Linux affected 20798dfe249a01ad1b12eec7dbc572db5003244a ab1016d39cc052064e32f25ad18ef8767a0ee3b8 git Not specified
CNA Linux Linux affected 5.13 Not specified
CNA Linux Linux unaffected 5.13 semver Not specified
CNA Linux Linux unaffected 5.13.4 5.13.* semver Not specified
CNA Linux Linux unaffected 5.14 * original_commit_for_fix Not specified
ADP Siemens RUGGEDCOM RST2428P unaffected * custom Not specified
ADP Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 Family unaffected * custom Not specified
ADP Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 Family unaffected * custom Not specified
ADP Siemens SIMATIC S7-1500 TM MFP - GNU/Linux Subsystem affected * custom Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/e79057d15d96ef19de4de6d7e479bae3d58a2a8d af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-265688.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-355557.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
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