---
id: CVE-2025-38023
title: 'nfs: handle failure of nfs_get_lock_context in unlock path'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nfs: handle failure of nfs_get_lock_context in unlock path

  When memory is insufficient, the allocation of nfs_lock_context in
  nfs_get_lock_context() fails and returns …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 <
    db6f5ee1fc8f54d079d0751292c2fc2d78e3aad1
  - >-
    Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 <
    4c189fd40a09a03f9a900bedb2d9064f1734d72a
  - >-
    Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 <
    72f552e00c50f265896d3c19edc6696aa2910081
  - >-
    Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 <
    85fb7f8ca5f8c138579fdfc9b97b3083e6077d40
  - >-
    Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 <
    a6879a076b98c99c9fe747816fe1c29543442441
  - >-
    Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 <
    da824f1271633bcb515ca8084cda3eda4b3ace51
  - >-
    Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 <
    f601960af04d2ecb007c928ba153d34051acd9c1
  - >-
    Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 <
    c457dc1ec770a22636b473ce5d35614adfe97636
  - Linux 4.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T20:48:18.289745Z'
published: '2025-06-18'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:52:12.741Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-38023'
references:
  - url: 'https://git.kernel.org/stable/c/db6f5ee1fc8f54d079d0751292c2fc2d78e3aad1'
  - url: 'https://git.kernel.org/stable/c/4c189fd40a09a03f9a900bedb2d9064f1734d72a'
  - url: 'https://git.kernel.org/stable/c/72f552e00c50f265896d3c19edc6696aa2910081'
  - url: 'https://git.kernel.org/stable/c/85fb7f8ca5f8c138579fdfc9b97b3083e6077d40'
  - url: 'https://git.kernel.org/stable/c/a6879a076b98c99c9fe747816fe1c29543442441'
  - url: 'https://git.kernel.org/stable/c/da824f1271633bcb515ca8084cda3eda4b3ace51'
  - url: 'https://git.kernel.org/stable/c/f601960af04d2ecb007c928ba153d34051acd9c1'
  - url: 'https://git.kernel.org/stable/c/c457dc1ec770a22636b473ce5d35614adfe97636'
tags:
  - cve.org
epss: 0.00228
epssPercentile: 0.13602
ingestedAt: '2026-11-05T22:38:31.908Z'
---

## Overview

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

nfs: handle failure of nfs_get_lock_context in unlock path

When memory is insufficient, the allocation of nfs_lock_context in
nfs_get_lock_context() fails and returns -ENOMEM. If we mistakenly treat
an nfs4_unlockdata structure (whose l_ctx member has been set to -ENOMEM)
as valid and proceed to execute rpc_run_task(), this will trigger a NULL
pointer dereference in nfs4_locku_prepare. For example:

BUG: kernel NULL pointer dereference, address: 000000000000000c
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 15 UID: 0 PID: 12 Comm: kworker/u64:0 Not tainted 6.15.0-rc2-dirty #60
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40
Workqueue: rpciod rpc_async_schedule
RIP: 0010:nfs4_locku_prepare+0x35/0xc2
Code: 89 f2 48 89 fd 48 c7 c7 68 69 ef b5 53 48 8b 8e 90 00 00 00 48 89 f3
RSP: 0018:ffffbbafc006bdb8 EFLAGS: 00010246
RAX: 000000000000004b RBX: ffff9b964fc1fa00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: fffffffffffffff4 RDI: ffff9ba53fddbf40
RBP: ffff9ba539934000 R08: 0000000000000000 R09: ffffbbafc006bc38
R10: ffffffffb6b689c8 R11: 0000000000000003 R12: ffff9ba539934030
R13: 0000000000000001 R14: 0000000004248060 R15: ffffffffb56d1c30
FS: 0000000000000000(0000) GS:ffff9ba5881f0000(0000) knlGS:00000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000000c CR3: 000000093f244000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __rpc_execute+0xbc/0x480
 rpc_async_schedule+0x2f/0x40
 process_one_work+0x232/0x5d0
 worker_thread+0x1da/0x3d0
 ? __pfx_worker_thread+0x10/0x10
 kthread+0x10d/0x240
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x34/0x50
 ? __pfx_kthread+0x10/0x10
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Modules linked in:
CR2: 000000000000000c
---[ end trace 0000000000000000 ]---

Free the allocated nfs4_unlockdata when nfs_get_lock_context() fails and
return NULL to terminate subsequent rpc_run_task, preventing NULL pointer
dereference.

## Affected

- `Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 < db6f5ee1fc8f54d079d0751292c2fc2d78e3aad1`
- `Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 < 4c189fd40a09a03f9a900bedb2d9064f1734d72a`
- `Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 < 72f552e00c50f265896d3c19edc6696aa2910081`
- `Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 < 85fb7f8ca5f8c138579fdfc9b97b3083e6077d40`
- `Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 < a6879a076b98c99c9fe747816fe1c29543442441`
- `Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 < da824f1271633bcb515ca8084cda3eda4b3ace51`
- `Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 < f601960af04d2ecb007c928ba153d34051acd9c1`
- `Linux >= f30cb757f680f965ba8a2e53cb3588052a01aeb5 < c457dc1ec770a22636b473ce5d35614adfe97636`
- `Linux 4.12`

## Remediation

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