---
id: CVE-2026-52908
title: 'RDMA: During rereg_mr ensure that REREG_ACCESS is compatible'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

  If IB_MR_REREG_ACCESS changes from RO to RW then the umem has to be
  re-evaluated to ensure it is properly …
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 >= b40656aa7d559adc1fe689396dc58b92a9a27286 <
    09dc18894148381d3bfc550083b1236043870dce
  - >-
    Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 <
    eba5df21eda0fe7418efbea2f799f8ea1b8ca94c
  - >-
    Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 <
    2904e985a2917b5dac65df82733065e78a65fc9d
  - >-
    Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 <
    50334a05a950840b39a1ce3d2a173b4183db9b3e
  - >-
    Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 <
    badad6fad60def1b9805559dd81dbab3d97b82aa
  - Linux 6.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:22:22.777962Z'
published: '2026-06-19'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:31:17.754Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-52908'
references:
  - url: 'https://git.kernel.org/stable/c/09dc18894148381d3bfc550083b1236043870dce'
  - url: 'https://git.kernel.org/stable/c/eba5df21eda0fe7418efbea2f799f8ea1b8ca94c'
  - url: 'https://git.kernel.org/stable/c/2904e985a2917b5dac65df82733065e78a65fc9d'
  - url: 'https://git.kernel.org/stable/c/50334a05a950840b39a1ce3d2a173b4183db9b3e'
  - url: 'https://git.kernel.org/stable/c/badad6fad60def1b9805559dd81dbab3d97b82aa'
tags:
  - cve.org
epss: 0.00129
epssPercentile: 0.02227
ingestedAt: '2026-10-16T17:24:46.718Z'
---

## Overview

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

RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

If IB_MR_REREG_ACCESS changes from RO to RW then the umem has to be
re-evaluated to ensure it is properly pinned as RW. Since the umem is
hidden inside each driver's mr struct add a ib_umem_check_rereg() function
that each driver has to call before processing IB_MR_REREG_ACCESS.

mlx4 has to retain its duplicate ib_access_writable check because it
implements IB_MR_REREG_ACCESS | IB_MR_REREG_TRANS by changing both items
in place sequentially while the MR is live, so it will continue to not
support this combination.

## Affected

- `Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 < 09dc18894148381d3bfc550083b1236043870dce`
- `Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 < eba5df21eda0fe7418efbea2f799f8ea1b8ca94c`
- `Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 < 2904e985a2917b5dac65df82733065e78a65fc9d`
- `Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 < 50334a05a950840b39a1ce3d2a173b4183db9b3e`
- `Linux >= b40656aa7d559adc1fe689396dc58b92a9a27286 < badad6fad60def1b9805559dd81dbab3d97b82aa`
- `Linux 6.2`

## Remediation

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