CVE-2026-89509 RDMA/ionic: Embed counter driver data in rdma_counter allocation
A missing driver adaptation in the Linux kernel RDMA/ionic driver causes a NULL pointer dereference, leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89509?
CVE-2026-89509 is a vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
RDMA/ionic: Embed counter driver data in rdma_counter allocation
Commit 7e53b31acc7f ("RDMA/core: Create and destroy rdma_counter using rdma_zalloc_drv_obj()") requires drivers implementing counter ops to embed struct rdma_counter in a driver-specific struct, register its size via INIT_RDMA_OBJ_SIZE, and provide a counter_init callback.
The ionic driver was merged without this adaptation, causing a NULL pointer dereference in alloc_and_bind() since rdma_zalloc_drv_obj() allocates zero bytes when size_rdma_counter is unset.
Consolidate struct ionic_counter into a new struct ionic_rdma_counter that embeds struct rdma_counter, replace the xarray with a lightweight ida for ID allocation, and add the required counter_init and INIT_RDMA_OBJ_SIZE declarations.
Which versions are affected by CVE-2026-89509?
How do I fix CVE-2026-89509?
Apply the vendor's patch.
Is CVE-2026-89509 being exploited?
There is no known exploitation of CVE-2026-89509 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-89509, DEBIAN-CVE-2026-89509, GHSA-p644-p7x2-xc3f, UBUNTU-CVE-2026-89509.