smb: client: pin DFS superblock in iterator callback
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
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 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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.158, 6.12.111, 6.18.53, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-97562
- 2026-10-03 Alias added: GHSA-38c4-cggv-4792
- 2026-10-03 Fix available: Linux/Linux@3c9acc9835c304013a4faeb969fe9333d66ca9f8, Linux/[email protected] · CNA
- 2026-10-03 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 5
- https://git.kernel.org/stable/c/3c9acc9835c304013a4faeb969fe9333d66ca9f8
- https://git.kernel.org/stable/c/ea43a15cea36dc5ddd832be5bddeac7dd804cbcf
- https://git.kernel.org/stable/c/a6b6561522212af852c9ad8a7dca8d59ef2c7377
- https://git.kernel.org/stable/c/5b01a8c0209690db75341528ec53fd87e0ac1460
- https://git.kernel.org/stable/c/d806d5a85dcbe2a0f181b2f0f9f61ddfbefa1818
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Sources
- CVE-2026-97562 · CVE Program
- CVE-2026-97562 · NVD
- FIRST EPSS
- GHSA-38c4-cggv-4792 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-97562 · Red Hat security data · CC BY 4.0
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