SB20261029205 - Heap-based buffer overflow in Linux kernel smb client

Description

This security bulletin contains information about 1 vulnerability.

1) Heap-based buffer overflow (CVE-ID: CVE-2026-99109)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service through kernel memory corruption.

The vulnerability exists due to a heap-based buffer overflow in the Linux kernel SMB client's CIFSSMBSetEA() function when processing extended attribute values on an SMB1 mount. A local user can invoke setxattr() with a specially crafted attribute name and value to write beyond the allocated request buffer and potentially crash the kernel.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/4aa2c106aef4bf3dfd97c30842db0767b26e8428
• https://git.kernel.org/stable/c/9efbd764ab80fa86d2258550877a74d78a25e855