SB2026092854 - Improper input validation in Linux kernel smb client
Published: September 28, 2026 Updated: September 30, 2026
Security Bulletin ID
SB2026092854
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Improper input validation (CVE-ID: CVE-2026-98127)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to bypass file-size limits.
The vulnerability exists due to improper validation of the calculated end-of-file size in smb3_insert_range() when handling FALLOC_FL_INSERT_RANGE requests on a CIFS mount. A local user can invoke fallocate with FALLOC_FL_INSERT_RANGE to bypass file-size limits.
Remediation
Install update from vendor's website.