Bug 2467012 (CVE-2026-43120)

Summary: CVE-2026-43120 kernel: RDMA/irdma: Fix double free related to rereg_user_mr
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's RDMA (Remote Direct Memory Access) irdma driver. This vulnerability, a double free, occurs during the re-registration of user memory regions. If an internal memory re-registration operation fails, the system attempts to free the same memory twice. This could allow a local attacker to cause memory corruption, potentially leading to a system crash (denial of service).
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Description OSIDB Bzimport 2026-05-06 10:03:08 UTC
In the Linux kernel, the following vulnerability has been resolved:

RDMA/irdma: Fix double free related to rereg_user_mr

If IB_MR_REREG_TRANS is set during rereg_user_mr, the
umem will be released and a new one will be allocated
in irdma_rereg_mr_trans. If any step of irdma_rereg_mr_trans
fails after the new umem is allocated, it releases the umem,
but does not set iwmr->region to NULL. The problem is that
this failure is propagated to the user, who will then call
ibv_dereg_mr (as they should). Then, the dereg_mr path will
see a non-NULL umem and attempt to call ib_umem_release again.

Fix this by setting iwmr->region to NULL after ib_umem_release.

Fixed: 5ac388db27c4 ("RDMA/irdma: Add support to re-register a memory region")