CVE-2026-68419 RDMA/irdma: Prevent rereg_mr for non-mem regions
A local attacker can trigger a denial of service in the Linux kernel by invoking rereg_mr on special RDMA memory regions with invalid keys.
- 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-2026-68419?
CVE-2026-68419 is a high-severity vulnerability in Linux, published on 10 Aug 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/irdma: Prevent rereg_mr for non-mem regions
When a QP/CQ/SRQ is created, a two step process is used where the buffer is allocated in userspace and explicitly registered with the normal reg_mr mechanism prior to creating the actual QP/CQ/SRQ object.
These special registrations are indicated via an ABI field so the driver knows that they do not have a valid mkey and to skip the actual CQP command submission.
Since these are real MR objects from the core's perspective, it is possible for a user application to invoke rereg_mr on them and cause a real CQP op to be emitted with the zero-initialized mkey value of 0.
Fix this by preventing rereg_mr on these special regions.
Weakness: CWE-20
Which versions are affected by CVE-2026-68419?
How do I fix CVE-2026-68419?
Apply the vendor's patch.
Is CVE-2026-68419 being exploited?
There is no known exploitation of CVE-2026-68419 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68419, DEBIAN-CVE-2026-68419, GHSA-f527-f42m-rc5q, UBUNTU-CVE-2026-68419.