CVE-2026-31432

About vulnerability

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix OOB write in QUERY_INFO for compound requests When a compound request such as READ + QUERY_INFO(Security) is received, and the first command (READ) consumes most of the response buffer, ksmbd could write beyond the allocated buffer while building a security descriptor. The root cause was that smb2_get_info_sec() checked buffer space using ppntsd_size from xattr, while build_sec_desc() often synthesized a significantly larger descriptor from POSIX ACLs. This patch introduces smb_acl_sec_desc_scratch_len() to accurately compute the final descriptor size beforehand, performs proper buffer checking with smb2_calc_max_out_buf_len(), and uses exact-sized allocation + iov pinning. A flaw was found in the ksmbd component of the Linux kernel. This vulnerability allows an attacker to cause the system to write data beyond its intended memory boundaries when processing specific network requests. Specifically, when a complex request combines data reading with security information queries, the system might miscalculate the required buffer size. This out-of-bounds write could lead to system instability, a denial of service, or potentially allow an attacker to execute malicious code.

Live-patch status from KernelCare for each operating system.