CVE-2026-93267 RDMA/core: Fix potential use after free in uverbs_free_dmah()
A use-after-free vulnerability in the Linux kernel RDMA subsystem allows local attackers to potentially execute code or escalate privileges via netlink access.
- 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-2026-93267?
CVE-2026-93267 is an use after free vulnerability in Linux, published on 24 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/core: Fix potential use after free in uverbs_free_dmah()
When accessing a dmah via the netlink path the only synchronization mechanism for the said dmah is rdma_restrack_get(). Currently, rdma_restrack_del() is invoked at the end of uverbs_free_dmah(), which is too late, since by that point vendor-specific resources associated with the dmah might already be freed. This can leave a short window where the dmah remains accessible through restrack, leading to a potential use-after-free.
Fix this by moving the rdma_restrack_begin_del() call to the start of uverbs_free_dmah(), ensuring that the dmah is removed from restrack before its internal resources are released. This guarantees that no new users hold references to a dmah that is in the process of destruction.
In addition, this change preserves the intended inverted order between create and destroy routines: resources are added to restrack at the end of successful creation, and hence shall be removed from the restrack first thing during the destruction flow, which keeps the lifecycle management consistent and predictable.
Which versions are affected by CVE-2026-93267?
How do I fix CVE-2026-93267?
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-2026-93267 being exploited?
There is no known exploitation of CVE-2026-93267 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-93267, DEBIAN-CVE-2026-93267, GHSA-w75x-m786-pw39, UBUNTU-CVE-2026-93267.