---
id: CVE-2026-43120
title: 'RDMA/irdma: Fix double free related to rereg_user_mr'
summary: |-
  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 ird…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 715fdb3b30541cc8180b7cdc6aa9f8c307afdf25 <
    62298a48f8b8788ad8b8464e6ffdf1ddebd2217e
  - >-
    Linux >= 5ac388db27c443dadfbb0b8b23fa7ccf429d901a <
    66964118f1f50ed85001c8fc9f7ab5bbdd021ee0
  - >-
    Linux >= 5ac388db27c443dadfbb0b8b23fa7ccf429d901a <
    0f22c32141acdcda266b26cab2b830baf870f3e0
  - >-
    Linux >= 5ac388db27c443dadfbb0b8b23fa7ccf429d901a <
    0c5d70bcb9d2275a1c8515a924016fcfeb4ab441
  - >-
    Linux >= 5ac388db27c443dadfbb0b8b23fa7ccf429d901a <
    29a3edd7004bb635d299fb9bc6f0ea4ef13ed5a2
  - Linux >= 6.6.120 < 6.6.136
  - Linux 6.7
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:14:52.649635Z'
published: '2026-05-06'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:33.540Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43120'
references:
  - url: 'https://git.kernel.org/stable/c/62298a48f8b8788ad8b8464e6ffdf1ddebd2217e'
  - url: 'https://git.kernel.org/stable/c/66964118f1f50ed85001c8fc9f7ab5bbdd021ee0'
  - url: 'https://git.kernel.org/stable/c/0f22c32141acdcda266b26cab2b830baf870f3e0'
  - url: 'https://git.kernel.org/stable/c/0c5d70bcb9d2275a1c8515a924016fcfeb4ab441'
  - url: 'https://git.kernel.org/stable/c/29a3edd7004bb635d299fb9bc6f0ea4ef13ed5a2'
tags:
  - cve.org
epss: 0.00175
epssPercentile: 0.06553
ingestedAt: '2026-10-16T17:24:46.683Z'
---

## Overview

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")

## Affected

- `Linux >= 715fdb3b30541cc8180b7cdc6aa9f8c307afdf25 < 62298a48f8b8788ad8b8464e6ffdf1ddebd2217e`
- `Linux >= 5ac388db27c443dadfbb0b8b23fa7ccf429d901a < 66964118f1f50ed85001c8fc9f7ab5bbdd021ee0`
- `Linux >= 5ac388db27c443dadfbb0b8b23fa7ccf429d901a < 0f22c32141acdcda266b26cab2b830baf870f3e0`
- `Linux >= 5ac388db27c443dadfbb0b8b23fa7ccf429d901a < 0c5d70bcb9d2275a1c8515a924016fcfeb4ab441`
- `Linux >= 5ac388db27c443dadfbb0b8b23fa7ccf429d901a < 29a3edd7004bb635d299fb9bc6f0ea4ef13ed5a2`
- `Linux >= 6.6.120 < 6.6.136`
- `Linux 6.7`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.