SB20261029206 - 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-2026-99110)

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 heap corruption.

The vulnerability exists due to a heap-based buffer overflow in the Linux kernel SMB client's cifs_do_set_acl() function when converting POSIX ACLs to the CIFS wire format. A local user can supply an ACL that passes validation based on the smaller extended-attribute representation but exceeds the destination buffer after conversion to corrupt kernel heap memory and potentially cause a denial of service.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29
• https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac
• https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98