ksmbd: Do not skip lock checks for single-byte ranges
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · None
- 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: Do not skip lock checks for single-byte ranges check_lock_range() uses inclusive ranges. Its callers pass the end offset as start + length - 1, so start == end represents a valid single-byte range rather than an empty range. The start == end shortcut therefore skips mandatory byte-range lock checks for one-byte reads, writes, copychunk operations and one-byte truncate ranges. A conflicting lock covering that byte is not checked and the operation is allowed to proceed. Remove the shortcut. The truncate size == inode->i_size case is already handled by only calling check_lock_range() when the new size differs from the current file size.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.1.160 to before 6.1.188; 6.6.120 to before 6.6.157; 6.12.64 to before 6.12.110; 6.18.3 to before 6.18.52 | 6.1.188, 6.6.157, 6.12.110, 6.18.52 | Patch available | CNA |
| Linux | Linux | 6.19 and later | 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 6.1.160 to before 6.1.188; 6.6.120 to before 6.6.157; 6.12.64 to before 6.12.110; 6.18.3 to before 6.18.52 Fixed in 6.1.188, 6.6.157, 6.12.110, 6.18.52 Patch available CNA
- Linux VendorLinux Affected 6.19 and later Fixed in 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.188, 6.6.157, 6.12.110, 6.18.52
- Fix · CNA Linux (Linux) Fixed in 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 7 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
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90176
- 2026-10-03 Alias added: GHSA-rxgv-prwv-26g4
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 6
- https://git.kernel.org/stable/c/a89cc145832e81c32199d4ca2e1ea8bd51ed601d
- https://git.kernel.org/stable/c/993e0158331d37c04da18efe551b5e1e35fb3078
- https://git.kernel.org/stable/c/f751d6e39d4c937c45f8fedc66699aa7d2d52288
- https://git.kernel.org/stable/c/84c2d8e807ac489f5c91769293fb15dfdae8bae8
- https://git.kernel.org/stable/c/07a9e289ff7edcc004f58952405f8a65c4e37512
- https://git.kernel.org/stable/c/d40c24634fe077a0dc91fd11fccf44ce12b454d5
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Sources
- CVE-2026-90176 · CVE Program
- CVE-2026-90176 · NVD
- FIRST EPSS
- GHSA-rxgv-prwv-26g4 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-90176 · Red Hat security data · CC BY 4.0
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