CVE-2026-43120: RDMA/irdma: Fix double free related to rereg_user_mr

Published May 6, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved:

RDMA/irdma: Fix double free related to reregusermr

If IBMRREREGTRANS is set during reregusermr, the umem will be released and a new one will be allocated in irdmareregmrtrans. If any step of irdmareregmrtrans 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 ibvderegmr (as they should). Then, the deregmr path will see a non-NULL umem and attempt to call ibumemrelease again.

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

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

Affected Software

10 affected components

Linux Linux kernel

Linux Linux kernel>=6.6.120<6.6.136

Linux Linux kernel>=6.7<6.12.83

Linux Linux kernel>=6.13<6.18.24

Linux Linux kernel>=6.19<6.19.14

Linux Linux kernel=7.0-rc1

Linux Linux kernel=7.0-rc2

Linux Linux kernel=7.0-rc3

Linux Linux kernel=7.0-rc4

Linux Linux kernel=7.0-rc5

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch 5ac388db27c4
Configuration
In the RDMA/irdma dereg_mr path, after calling ib_umem_release, set iwmr->region to NULL to prevent a double ib_umem_release during rereg_user_mr/irdma_rereg_mr_trans.
Linux kernel (RDMA/irdma) iwmr->region = NULL

Event History

May 6, 2026

CVE Published

via MITRE·07:40 AM

Data Sourced

via MITRE·07:40 AM

DescriptionSeverity

Data Sourced

via NVD·10:16 AM

RemedyDescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

What is the severity of CVE-2026-43120?

CVE-2026-43120 has a medium severity rating, primarily affecting the RDMA subsystem of the Linux kernel.

How do I fix CVE-2026-43120?

To fix CVE-2026-43120, update to the patched version of the Linux kernel that has addressed the double free vulnerability.

What makes CVE-2026-43120 a concern for Linux kernel users?

CVE-2026-43120 is a concern as it can lead to memory corruption and potential system instability if exploited.

Which Linux kernel versions are affected by CVE-2026-43120?

CVE-2026-43120 affects multiple versions of the Linux kernel that utilize the RDMA and irdma subsystems.

Is there a public exploit for CVE-2026-43120?

As of now, no public exploit for CVE-2026-43120 has been reported, but users are advised to apply patches promptly.