CVE-2026-90435 RDMA/mlx5: Fix integer overflow of user QP buffer size
A signed integer overflow in the Linux kernel RDMA driver allows attackers to map undersized buffers, potentially leading to memory corruption and privilege escalation.
- 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-2026-90435?
CVE-2026-90435 is a high-severity vulnerability in Linux, published on 17 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/mlx5: Fix integer overflow of user QP buffer size
set_user_buf_size() computes the QP buffer size by left-shifting the user-supplied rq.wqe_cnt and rq.wqe_shift values as signed integers. A sufficiently large rq.wqe_cnt causes signed integer overflow, which is undefined behavior, and yields a small or negative buf_size, causing ib_umem_get() to map a buffer smaller than the hardware will actually write into.
Replace the shifts and addition with check_shl_overflow() and check_add_overflow(), rejecting invalid user inputs.
Moreover, guard the identical shift computing qp->sq.offset in _create_user_qp() before set_user_buf_size() is reached.
Which versions are affected by CVE-2026-90435?
How do I fix CVE-2026-90435?
Apply the vendor's patch.
Is CVE-2026-90435 being exploited?
There is no known exploitation of CVE-2026-90435 in the wild and no public exploit code.
Sources
Also known as AZL-102194, BELL-CVE-2026-90435, DEBIAN-CVE-2026-90435, GHSA-4ff5-3w52-wwv7, UBUNTU-CVE-2026-90435.