CVE-2026-89505

In the Linux kernel, the following vulnerability has been resolved:

RDMA/uverbs: Guard legacy bundles without method elm

The legacy write() path dispatches through a uverbs api write method, but the uverbs attr bundle passed to provider code does not have an ioctl method element. If malformed provider input causes the common uverbs validation code to emit an error message, uverbs get handler fn() dereferences the uninitialized method elm pointer.

Initialize method elm explicitly for legacy bundles and make uverbs get handler fn() return NULL when no ioctl method is present. The legacy dispatcher continues to use its local write method, while the ioctl path continues to use the registered ioctl handler.