ksmbd: fix use-after-free in __close_file_table_ids()
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in __close_file_table_ids() A ksmbd_file can remain alive after logical close while another session holds a temporary reference obtained through ksmbd_lookup_fd_inode(). ksmbd_close_fd() currently marks the file closed and drops the idr-owned reference, but leaves the pointer published in the closing session's idr until the final reference is dropped. If the foreign holder performs the final ksmbd_fd_put(), __put_fd_final() supplies the foreign session's file table to __ksmbd_close_fd(). The object is then freed without being removed from its owner's idr, and the owner session later dereferences the stale pointer during file-table teardown. Remove the volatile id from the owner's idr while ksmbd_close_fd() still holds that table's lock, and clear volatile_id before dropping the idr-owned reference. A later foreign final put then only performs physical destruction and cannot remove the object from the wrong table.
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 5.16, 5.18
- Fix · CNA Linux (Linux) Fixed in 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74522
- 2026-10-03 Alias added: GHSA-r5jm-2247-f5r8
- 2026-10-28 EPSS moved to the 50th–90th percentile
- 2026-11-06 EPSS moved to the below the 50th percentile
References
Other 6
- https://git.kernel.org/stable/c/19bfd90d5aaf63217735d81964585c5306158e5f
- https://git.kernel.org/stable/c/67aaec2a1fdce3e1dde46c45b5d1ef8cf22f65cd
- https://git.kernel.org/stable/c/0c3918c2cee62ec6c9de8d5c73ebfe6f833961ac
- https://git.kernel.org/stable/c/9be4a66f019ea90bd9deca70511f4f9ffebf5c6f
- https://git.kernel.org/stable/c/cffbdc86393b0235383a20c8c59bc32f16036459
- https://git.kernel.org/stable/c/e7188199eff46a636f3436356f0aae039be6dd66
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Sources
- CVE-2026-74522 · CVE Program
- CVE-2026-74522 · NVD
- FIRST EPSS
- GHSA-r5jm-2247-f5r8 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74522 · Red Hat security data · CC BY 4.0
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