CVE-2026-97562
HIGHDescription
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 v3 vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Affected routers (0)
No routers currently mapped to this CVE in our database.