SB2026092569 - Race condition in Linux kernel smb client

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-93794)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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 cause punched file ranges to be incorrectly reported as allocated data.

The vulnerability exists due to improper synchronization in the SMB client smb3_punch_hole function when punching a hole after a large buffered write. A local user can perform a large buffered write followed by a hole-punch operation to cause punched file ranges to be incorrectly reported as allocated data.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/39562a56cdb515f6635c3e7bfe6629439b18a169
• https://git.kernel.org/stable/c/6c265aca08155e519a8f6f6071c59dff4f535f70
• https://git.kernel.org/stable/c/d7d2adcd022baade5cab65ca492ce63421ce3a6e