---
id: CVE-2026-97562
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smb: client: pin DFS superblock in iterator callback

  tcon_super_cb() stores a raw superblock pointer, but __cifs_get_super()
  takes its active reference only after iter…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smb: client: pin DFS superblock in iterator callback

  tcon_super_cb() stores a raw superblock pointer, but __cifs_get_super()
  takes its active reference only after iter…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= bacd704a95ad0b93af995aae4a523aa046f46563 <
    ea43a15cea36dc5ddd832be5bddeac7dd804cbcf
  - >-
    Linux >= bacd704a95ad0b93af995aae4a523aa046f46563 <
    a6b6561522212af852c9ad8a7dca8d59ef2c7377
  - >-
    Linux >= bacd704a95ad0b93af995aae4a523aa046f46563 <
    5b01a8c0209690db75341528ec53fd87e0ac1460
  - >-
    Linux >= bacd704a95ad0b93af995aae4a523aa046f46563 <
    d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818
  - Linux 5.7
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T15:17:59.183'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97562'
references:
  - url: 'https://git.kernel.org/stable/c/5b01a8c0209690db75341528ec53fd87e0ac1460'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a6b6561522212af852c9ad8a7dca8d59ef2c7377'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ea43a15cea36dc5ddd832be5bddeac7dd804cbcf'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.915Z'
---

## Overview

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

smb: client: pin DFS superblock in iterator callback

tcon_super_cb() stores a raw superblock pointer, but __cifs_get_super()
takes its active reference only after iterate_supers_type() has dropped
s_umount and its passive reference. Concurrent DFS automount expiry can
therefore free the superblock before cifs_sb_active() uses it.

A deterministic KASAN test reproduces the race as:

  BUG: KASAN: slab-use-after-free in cifs_sb_active+0x77/0x80

The same test passes with this change applied.

Take the active reference in the callback while iterate_supers_type()
still holds s_umount shared. cifs_put_tcp_super() remains the matching
release.

## Remediation

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