IM
IronMonkey Threat Research

CVE-2021-47316 HIGH

Published: 2024-05-21 | Last Modified: 2026-08-04 | Status: Modified

Description

In 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.

Additional Descriptions (1)

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nfsd: corrige la desreferencia NULL en nfs3svc_encode_getaclres. En casos de error, la dentry puede ser NULL. Antes de 20798dfe249a, el codificador también verificaba dentry y d_really_is_positive(dentry), pero eso me parece excesivo: el estado cero debería ser suficiente para garantizar un dentry positivo. Esta no es la primera vez que vemos una desreferencia NULL de caso de error oculta en la inicialización de una variable local en un codificador xdr. Pero revisé las otras reescrituras recientes y no encontré ningún error similar.

CVSS Metrics

Base Score: 5.5 (MEDIUM)

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

Attack VectorLOCAL
Attack ComplexityLOW
Privileges RequiredLOW
User InteractionNONE
ScopeUNCHANGED
Confidentiality ImpactNONE
Integrity ImpactNONE
Availability ImpactHIGH

Source: [email protected]

Type: Primary

Exploitability Score: 1.8

Impact Score: 3.6

Weaknesses

Source Type Description
[email protected] Primary
en CWE-476

Affected Products

Vendor Product Version Update Type
linux linux_kernel * <built-in method update of dict object at 0x7fd3412407c0> Operating System

Affected Configurations

Operator: OR

Vulnerable CPE
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

References