CVE-2026-31707

취약점 유형

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate response sizes in ipc_validate_msg() ipc_validate_msg() computes the expected message size for each response type by adding (or multiplying) attacker-controlled fields from the daemon response to a fixed struct size in unsigned int arithmetic. Three cases can overflow: KSMBD_EVENT_RPC_REQUEST: msg_sz = sizeof(struct ksmbd_rpc_command) + resp->payload_sz; KSMBD_EVENT_SHARE_CONFIG_REQUEST: msg_sz = sizeof(struct ksmbd_share_config_response) + resp->payload_sz; KSMBD_EVENT_LOGIN_REQUEST_EXT: msg_sz = sizeof(struct ksmbd_login_response_ext) + resp->ngroups * sizeof(gid_t); resp->payload_sz is __u32 and resp->ngroups is __s32. Each addition can wrap in unsigned int; the multiplication by sizeof(gid_t) mixes signed and size_t, so a negative ngroups is converted to SIZE_MAX before the multiply. A wrapped value of msg_sz that happens to equal entry->msg_sz bypasses the size check on the next line, and downstream consumers (smb2pdu.c:6742 memcpy using rpc_resp->payload_sz, kmemdup in ksmbd_alloc_user using resp_ext->ngroups) then trust the unverified length. Use check_add_overflow() on the RPC_REQUEST and SH

영향받는 제품

• linux linux_kernel

참고 자료

• https://git.kernel.org/stable/c/299db777ea0cfa5c407e41b045c24a14c034c27b
• https://git.kernel.org/stable/c/7dd0c858e1909769a4c91842724315ee74f1a5f1
• https://git.kernel.org/stable/c/99c631d0366c1eab8fb188fe66425f4581ebdde4
• https://git.kernel.org/stable/c/bf396208418371174869baba9434535cd3288e80
• https://git.kernel.org/stable/c/d6a6aa81eac2c9bff66dc6e191179cb69a14426b