---
id: CVE-2023-54258
title: 'cifs: fix potential oops in cifs_oplock_break'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cifs: fix potential oops in cifs_oplock_break

  With deferred close we can have closes that race with lease breaks,
  and so with the current checks for whether to send th…
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'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 63fb45ddc491895c4b36664e0c2c3b548545ae93 <
    b99f490ea87ebcca3a429fd8837067feb56a4c7c
  - >-
    Linux >= 1bf709b9625001eefdd41048c5f4c7544ee33394 <
    5ee28bcfbaacf289eb25c662a2862542ea6ce6a7
  - >-
    Linux >= 3b4c15171c3ce9120c81f5564b9367d8d0f4219c <
    6b67a6d2e50634fe127e656147c81915955e9f5e
  - >-
    Linux >= da787d5b74983f7525d1eb4b9c0b4aff2821511a <
    e8f5f849ffce24490eb9449e98312b66c0dba76f
  - Linux cff7fb969edaeff2bc80c8a8f7cf7b0c8df32da7
  - Linux >= 6.3.13 < 6.4
  - Linux >= 5.15.121 < 5.15.128
  - Linux >= 6.1.39 < 6.1.47
  - Linux >= 6.4.4 < 6.4.12
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-15T21:39:50.673035Z'
published: '2025-12-30'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T21:41:43.411Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-54258'
references:
  - url: 'https://git.kernel.org/stable/c/b99f490ea87ebcca3a429fd8837067feb56a4c7c'
  - url: 'https://git.kernel.org/stable/c/5ee28bcfbaacf289eb25c662a2862542ea6ce6a7'
  - url: 'https://git.kernel.org/stable/c/6b67a6d2e50634fe127e656147c81915955e9f5e'
  - url: 'https://git.kernel.org/stable/c/e8f5f849ffce24490eb9449e98312b66c0dba76f'
tags:
  - cve.org
epss: 0.00555
epssPercentile: 0.44964
ingestedAt: '2026-10-15T22:48:25.436Z'
---

## Overview

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

cifs: fix potential oops in cifs_oplock_break

With deferred close we can have closes that race with lease breaks,
and so with the current checks for whether to send the lease response,
oplock_response(), this can mean that an unmount (kill_sb) can occur
just before we were checking if the tcon->ses is valid.  See below:

[Fri Aug  4 04:12:50 2023] RIP: 0010:cifs_oplock_break+0x1f7/0x5b0 [cifs]
[Fri Aug  4 04:12:50 2023] Code: 7d a8 48 8b 7d c0 c0 e9 02 48 89 45 b8 41 89 cf e8 3e f5 ff ff 4c 89 f7 41 83 e7 01 e8 82 b3 03 f2 49 8b 45 50 48 85 c0 74 5e <48> 83 78 60 00 74 57 45 84 ff 75 52 48 8b 43 98 48 83 eb 68 48 39
[Fri Aug  4 04:12:50 2023] RSP: 0018:ffffb30607ddbdf8 EFLAGS: 00010206
[Fri Aug  4 04:12:50 2023] RAX: 632d223d32612022 RBX: ffff97136944b1e0 RCX: 0000000080100009
[Fri Aug  4 04:12:50 2023] RDX: 0000000000000001 RSI: 0000000080100009 RDI: ffff97136944b188
[Fri Aug  4 04:12:50 2023] RBP: ffffb30607ddbe58 R08: 0000000000000001 R09: ffffffffc08e0900
[Fri Aug  4 04:12:50 2023] R10: 0000000000000001 R11: 000000000000000f R12: ffff97136944b138
[Fri Aug  4 04:12:50 2023] R13: ffff97149147c000 R14: ffff97136944b188 R15: 0000000000000000
[Fri Aug  4 04:12:50 2023] FS:  0000000000000000(0000) GS:ffff9714f7c00000(0000) knlGS:0000000000000000
[Fri Aug  4 04:12:50 2023] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[Fri Aug  4 04:12:50 2023] CR2: 00007fd8de9c7590 CR3: 000000011228e000 CR4: 0000000000350ef0
[Fri Aug  4 04:12:50 2023] Call Trace:
[Fri Aug  4 04:12:50 2023]  <TASK>
[Fri Aug  4 04:12:50 2023]  process_one_work+0x225/0x3d0
[Fri Aug  4 04:12:50 2023]  worker_thread+0x4d/0x3e0
[Fri Aug  4 04:12:50 2023]  ? process_one_work+0x3d0/0x3d0
[Fri Aug  4 04:12:50 2023]  kthread+0x12a/0x150
[Fri Aug  4 04:12:50 2023]  ? set_kthread_struct+0x50/0x50
[Fri Aug  4 04:12:50 2023]  ret_from_fork+0x22/0x30
[Fri Aug  4 04:12:50 2023]  </TASK>

To fix this change the ordering of the checks before sending the oplock_response
to first check if the openFileList is empty.

## Affected

- `Linux >= 63fb45ddc491895c4b36664e0c2c3b548545ae93 < b99f490ea87ebcca3a429fd8837067feb56a4c7c`
- `Linux >= 1bf709b9625001eefdd41048c5f4c7544ee33394 < 5ee28bcfbaacf289eb25c662a2862542ea6ce6a7`
- `Linux >= 3b4c15171c3ce9120c81f5564b9367d8d0f4219c < 6b67a6d2e50634fe127e656147c81915955e9f5e`
- `Linux >= da787d5b74983f7525d1eb4b9c0b4aff2821511a < e8f5f849ffce24490eb9449e98312b66c0dba76f`
- `Linux cff7fb969edaeff2bc80c8a8f7cf7b0c8df32da7`
- `Linux >= 6.3.13 < 6.4`
- `Linux >= 5.15.121 < 5.15.128`
- `Linux >= 6.1.39 < 6.1.47`
- `Linux >= 6.4.4 < 6.4.12`

## Remediation

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