Vulnerability record · CVE-2026-97562 · published 25 September 2026
CVE-2026-97562: In the Linux kernel, the following vulnerability has been resolved: smb: client: pin DFS superblock in iterat…
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.
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
References
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Source: NIST National Vulnerability Database (record CVE-2026-97562), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.
