CVE-2026-97562

smb: client: pin DFS superblock in iterator callback

HIGH
7.5
CVSS Score
Published: September 25, 2026 at 10:21 AM UTC
Updated: October 19, 2026 at 10:17 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.7bacd704a95ad0b93af995aae4a523aa046f46563
Vendor states this is fixed in 3c9acc9835c304013a4faeb969fe9333d66ca9f8 (fixed)
Vendor states this is fixed in 5b01a8c0209690db75341528ec53fd87e0ac1460 (fixed)
Vendor states this is fixed in a6b6561522212af852c9ad8a7dca8d59ef2c7377 (fixed)
Vendor states this is fixed in d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818 (fixed)
Vendor states this is fixed in ea43a15cea36dc5ddd832be5bddeac7dd804cbcf (fixed)
Vendor states this is fixed in 5.7 (unaffected)
Vendor states this is fixed in 6.12.111 (unaffected)
Vendor states this is fixed in 6.18.53 (unaffected)
Vendor states this is fixed in 6.6.158 (unaffected)
Vendor states this is fixed in 7.2.7 (unaffected)
Vendor states this is fixed in 7.3 (unaffected)
Vendor states this is fixed in 7.3-rc3 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

7.5HIGHLinux
Vector?

Quick Info

StatusRECEIVED

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