CVE-2026-90176

Updated on 17 Sep 2026

Severity

8.1 High severity

Details

CVSS score
8.1

Overview

About vulnerability

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.

Details

KernelCare state

Live-patch status from KernelCare for each operating system.

Operating system Status Covered kernels
Debian 12 Planned —
Debian 13 Released
16 kernels
  • 6.12.85-1
  • 6.12.86-1
  • 6.12.88-1
  • 6.12.74-2
  • 6.12.73-1
  • 6.12.69-1
  • 6.12.74-1
  • 6.12.90-1
  • 6.12.90-2
  • 6.12.94-1
  • 6.12.95-1
  • 6.12.96-1
  • 6.12.100-1
  • 6.12.101-1
  • 6.12.105-1
  • 6.12.107-1