CVE-2026-45856

In the Linux kernel, the following vulnerability has been resolved: RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send ib_uverbs_post_send() uses cmd.wqe_size from userspace without any validation before passing it to kmalloc() and using the allocated buffer as struct ib_uverbs_send_wr. If a user provides a small wqe_size value (e.g., 1), kmalloc() will succeed, but subsequent accesses to user_wr->opcode, user_wr->num_sge, and other fields will read beyond the allocated buffer, resulting in an out-of-bounds read from kernel heap memory. This could potentially leak sensitive kernel information to userspace. Additionally, providing an excessively large wqe_size can trigger a WARNING in the memory allocation path, as reported by syzkaller. This is inconsistent with ib_uverbs_unmarshall_recv() which properly validates that wqe_size >= sizeof(struct ib_uverbs_recv_wr) before proceeding. Add the same validation for ib_uverbs_post_send() to ensure wqe_size is at least sizeof(struct ib_uverbs_send_wr).

• linux linux kernel (>= 5.0 < 5.10.252) • linux linux kernel (>= 5.11 < 5.15.202) • linux linux kernel (>= 5.16 < 6.1.165) • linux linux kernel (>= 6.2 < 6.6.128) • linux linux kernel (>= 6.7 < 6.12.75) • linux linux kernel (>= 6.13 < 6.18.14) • linux linux kernel (>= 6.19 < 6.19.4)