CVE-2026-90423 RDMA/rxe: Fix UAF in ODP init error-handling path
A use-after-free vulnerability in the Linux kernel's RDMA/rxe driver allows attackers to potentially execute code or escalate privileges via improper error handling in ODP initialization.
- 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-2026-90423?
CVE-2026-90423 is a high-severity use after free 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/rxe: Fix UAF in ODP init error-handling path
rxe_odp_mr_init_user() stores &umem_odp->umem in mr->umem before calling rxe_odp_init_pages(). If rxe_odp_init_pages() fails, rxe_odp_mr_init_user() releases umem_odp and returns an error.
rxe_reg_user_mr() then unwinds the error through rxe_cleanup(), rxe_mr_cleanup(), ib_umem_release(mr->umem). There is an IS_ERR_OR_NULL(umem) check at the start of ib_umem_release(). But since mr->umem is NOT reset to NULL in the error handling path of rxe_odp_mr_init_user(), the check passes and it reads already-freed fields like umem->is_dmabuf, causing UAF.
Fix the UAF by clearing mr->umem after releasing the failed ODP umem so the MR cleanup path does not release it again.
Which versions are affected by CVE-2026-90423?
How do I fix CVE-2026-90423?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-90423 being exploited?
There is no known exploitation of CVE-2026-90423 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90423, DEBIAN-CVE-2026-90423, GHSA-vg4x-c29w-66xm, UBUNTU-CVE-2026-90423.