---
id: CVE-2026-90435
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  RDMA/mlx5: Fix integer overflow of user QP buffer size

  set_user_buf_size() computes the QP buffer size by left-shifting the
  user-supplied rq.wqe_cnt and rq.wqe_shift v…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  RDMA/mlx5: Fix integer overflow of user QP buffer size

  set_user_buf_size() computes the QP buffer size by left-shifting the
  user-supplied rq.wqe_cnt and rq.wqe_shift v…
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'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c <
    ccce6b7ef1d7efc59ccba3421e1339c6e63a3d20
  - >-
    Linux >= e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c <
    d99622e40aaa910ade681dfd4dc0fa240a011331
  - >-
    Linux >= e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c <
    c845e5e05140ea1bc64a5b1107942d93c876034d
  - >-
    Linux >= e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c <
    42fb8aefffff5b458aaa66803364a16e0ea44129
  - >-
    Linux >= e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c <
    d7fa2ff72ad1861eac194a4e0075d504ba8c246e
  - >-
    Linux >= e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c <
    5b6cfc6d7ff0959dd9766fdc24286a253b59ca77
  - >-
    Linux >= e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c <
    f917707f0de0832b8ab582391b1f64e549995c6c
  - >-
    Linux >= e126ba97dba9edeb6fafa3665b5f8497fc9cdf8c <
    dec47e4b0fe34afdf38caa72b4408ba95502e5de
  - Linux 3.11
published: '2026-09-17'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:17:59.280'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90435'
references:
  - url: 'https://git.kernel.org/stable/c/42fb8aefffff5b458aaa66803364a16e0ea44129'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5b6cfc6d7ff0959dd9766fdc24286a253b59ca77'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c845e5e05140ea1bc64a5b1107942d93c876034d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ccce6b7ef1d7efc59ccba3421e1339c6e63a3d20'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d7fa2ff72ad1861eac194a4e0075d504ba8c246e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d99622e40aaa910ade681dfd4dc0fa240a011331'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dec47e4b0fe34afdf38caa72b4408ba95502e5de'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f917707f0de0832b8ab582391b1f64e549995c6c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00129
epssPercentile: 0.02904
ingestedAt: '2026-09-17T16:21:47.790Z'
---

## Overview

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

RDMA/mlx5: Fix integer overflow of user QP buffer size

set_user_buf_size() computes the QP buffer size by left-shifting the
user-supplied rq.wqe_cnt and rq.wqe_shift values as signed integers.
A sufficiently large rq.wqe_cnt causes signed integer overflow, which
is undefined behavior, and yields a small or negative buf_size, causing
ib_umem_get() to map a buffer smaller than the hardware will actually
write into.

Replace the shifts and addition with check_shl_overflow() and
check_add_overflow(), rejecting invalid user inputs.

Moreover, guard the identical shift computing qp->sq.offset in
_create_user_qp() before set_user_buf_size() is reached.

## Remediation

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