---
id: CVE-2026-90151
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  NFSv4: remove callback IDR entry on client allocation failure

  nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it
  finishes setting up the client
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  NFSv4: remove callback IDR entry on client allocation failure

  nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it
  finishes setting up the client. If…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= f4eecd5da3422e82e88e36c33cbd2595eebcacb1 <
    68c721391b761dbe38d5b0094d2bb6e8489ad92b
  - >-
    Linux >= f4eecd5da3422e82e88e36c33cbd2595eebcacb1 <
    9bfdd0f591307b5198826a0e7a5b2f35f87acd2d
  - >-
    Linux >= f4eecd5da3422e82e88e36c33cbd2595eebcacb1 <
    7c4812eb96bdcafb31a65b12f2aa96659429d1d4
  - >-
    Linux >= f4eecd5da3422e82e88e36c33cbd2595eebcacb1 <
    fc95ca82d5ae598c428ab5a00ae69f8526d59371
  - >-
    Linux >= f4eecd5da3422e82e88e36c33cbd2595eebcacb1 <
    80b1c3d5a881f7d9081aa9f46da9742878a0f893
  - >-
    Linux >= f4eecd5da3422e82e88e36c33cbd2595eebcacb1 <
    3f2387e8bfbc4efda5d77c3a11a028d0a119c48f
  - >-
    Linux >= f4eecd5da3422e82e88e36c33cbd2595eebcacb1 <
    5891c03e150920618db0e9c4ea2d772abacdcfd1
  - >-
    Linux >= f4eecd5da3422e82e88e36c33cbd2595eebcacb1 <
    d05c2007b3d84ccba11dc6e9cb3202768cc72f14
  - Linux 2.6.38
published: '2026-09-17'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:17:44.250'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90151'
references:
  - url: 'https://git.kernel.org/stable/c/3f2387e8bfbc4efda5d77c3a11a028d0a119c48f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5891c03e150920618db0e9c4ea2d772abacdcfd1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/68c721391b761dbe38d5b0094d2bb6e8489ad92b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7c4812eb96bdcafb31a65b12f2aa96659429d1d4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/80b1c3d5a881f7d9081aa9f46da9742878a0f893'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9bfdd0f591307b5198826a0e7a5b2f35f87acd2d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d05c2007b3d84ccba11dc6e9cb3202768cc72f14'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fc95ca82d5ae598c428ab5a00ae69f8526d59371'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00793
epssPercentile: 0.54487
ingestedAt: '2026-09-17T16:21:47.877Z'
---

## Overview

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

NFSv4: remove callback IDR entry on client allocation failure

nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it
finishes setting up the client. If any later initialization step fails,
the error path frees the nfs_client directly with nfs_free_client(). That
bypasses nfs_put_client(), which is where the callback IDR entry is
removed during normal teardown.

A failed allocation can therefore leave cb_ident_idr pointing at a freed
nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the
stale pointer and take a reference to it.

Make the callback IDR removal helper callable by the allocation failure
path, and remove the callback identifier before freeing the client.

This was found by a local static-analysis checker for publish-before-free
lifetime bugs and confirmed by manual inspection.

## Remediation

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