CVE-2026-110714

libsmb2 through 6.2 contains an integer underflow vulnerability in decode_acl that allows malicious SMB servers to trigger heap out-of-bounds reads via crafted security descriptors. Attackers controlling a server or intercepting unsigned sessions can send an AclSize below 8 in a QUERY_INFO reply, bypassing ACE bounds checks and crashing the client.

• https://github.com/sahlberg/libsmb2
• https://github.com/sahlberg/libsmb2/blob/d67e213a5c4e7e4969fd81f0b95e4ca5831fbba1/lib/smb2-data-security-descriptor.c#L266
• https://github.com/sahlberg/libsmb2/commit/523abe20be3207011a936db47f1d3bab79c05450
• https://hackmd.io/@haind-pwn/libsmb2-query-info-reply-oob-read
• https://www.vulncheck.com/advisories/libsmb2-through-6.2-heap-out-of-bounds-read-via-decode-acl-integer-underflow