Bug 2513475 (CVE-2026-68419)

Summary: CVE-2026-68419 kernel: RDMA/irdma: Prevent rereg_mr for non-mem regions
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's RDMA/irdma component. A local user could exploit this by attempting to re-register specific memory regions (Queue Pair, Completion Queue, or Shared Receive Queue objects) that are not intended for re-registration. This could lead to an invalid operation being performed with a zero-initialized memory key, potentially causing system instability.
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Description OSIDB Bzimport 2026-08-10 12:39:27 UTC 
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.
Comment 1 Mauro Matteo Cascella 2026-08-11 08:10:39 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081051-CVE-2026-68419-8aca@gregkh/T