SB2026110857 - Out-of-bounds write in Linux kernel smb server

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-99273)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote user to corrupt kernel memory, potentially causing a denial of service.

The vulnerability exists due to an out-of-bounds write in the Linux kernel ksmbd get_file_stream_info() function when generating stream information without reserving space for a terminating UTF-16 unit. A remote user can trigger processing of a stream entry that exactly fills the 448-byte response buffer to cause a two-byte write past the allocation, potentially causing a denial of service.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/06a751809ebd33e95b05bf733697318a17a4872b
• https://git.kernel.org/stable/c/0e64f89563164719ceb1aa33f2a8bfd6391fa340
• https://git.kernel.org/stable/c/a025c4991a7d83edc4dd339e3ea86d8ff6226eca