---
id: CVE-2025-40326
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  NFSD: Define actions for the new time_deleg FATTR4 attributes

  NFSv4 clients won't send legitimate GETATTR requests for these new
  attributes because they are intended t…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  NFSD: Define actions for the new time_deleg FATTR4 attributes

  NFSv4 clients won't send legitimate GETATTR requests for these new
  attributes because they are intended t…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
published: '2025-12-08'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T22:10:00.210'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-40326'
references:
  - url: 'https://git.kernel.org/stable/c/4f76435fd517981f01608678c06ad9718a86ee98'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d8f3f94dc950e7c62c96af432c26745885b0a18a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.0035
epssPercentile: 0.26968
ingestedAt: '2026-10-14T23:00:02.026Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

NFSD: Define actions for the new time_deleg FATTR4 attributes

NFSv4 clients won't send legitimate GETATTR requests for these new
attributes because they are intended to be used only with CB_GETATTR
and SETATTR. But NFSD has to do something besides crashing if it
ever sees a GETATTR request that queries these attributes.

RFC 8881 Section 18.7.3 states:

> The server MUST return a value for each attribute that the client
> requests if the attribute is supported by the server for the
> target file system. If the server does not support a particular
> attribute on the target file system, then it MUST NOT return the
> attribute value and MUST NOT set the attribute bit in the result
> bitmap. The server MUST return an error if it supports an
> attribute on the target but cannot obtain its value. In that case,
> no attribute values will be returned.

Further, RFC 9754 Section 5 states:

> These new attributes are invalid to be used with GETATTR, VERIFY,
> and NVERIFY, and they can only be used with CB_GETATTR and SETATTR
> by a client holding an appropriate delegation.

Thus there does not appear to be a specific server response mandated
by specification. Taking the guidance that querying these attributes
via GETATTR is "invalid", NFSD will return nfserr_inval, failing the
request entirely.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.