CVE Catalog

CVE-2026-97562

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Summary

In the Linux kernel SMB client, 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, resulting in a use-after-free. The fix takes the active reference in the callback while iterate_supers_type() still holds s_umount shared.

Risk Assessment

Triggering the race condition can cause a use-after-free in the kernel, risking system crash or potentially arbitrary code execution in kernel context. The risk applies to systems using CIFS DFS automounting.

Recommendation

Update the Linux kernel to a version containing the fix that takes the active superblock reference in the iterator callback. Avoid concurrent DFS automount expiry during superblock operations if immediate update is not possible.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS