---
id: CVE-2026-74378
title: 'RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe

  get_srq_wqe() reads wqe->dma.num_sge from the shared receive queue
  buffer, which is mapped into userspace. It validat…
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 >= 8700e3e7c4857d28ebaa824509934556da0b3e76 <
    c8db0e5ab0b6c540214c46c56aaac7cbcb0967fe
  - >-
    Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 <
    e48daa94ad2d406225b73491fc935064716f0ec7
  - >-
    Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 <
    3cfa2a3adc51b7c57729961a03446962ff10e3d2
  - >-
    Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 <
    cd19a6345e3727adafafa5954b58b13c92e13b80
  - >-
    Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 <
    3e07ea9579dc9553d2285c26c2823931358aa3b8
  - >-
    Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 <
    02558c86b6b761063e9399e6b939984500327ef1
  - >-
    Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 <
    b9800d7953d119bcc068c74587d48e4ba0313629
  - >-
    Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 <
    22b8fbded65b8c441b634a185f8da67657df6c50
  - Linux 4.8
published: '2026-08-15'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T11:58:46.129Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74378'
references:
  - url: 'https://git.kernel.org/stable/c/c8db0e5ab0b6c540214c46c56aaac7cbcb0967fe'
  - url: 'https://git.kernel.org/stable/c/e48daa94ad2d406225b73491fc935064716f0ec7'
  - url: 'https://git.kernel.org/stable/c/3cfa2a3adc51b7c57729961a03446962ff10e3d2'
  - url: 'https://git.kernel.org/stable/c/cd19a6345e3727adafafa5954b58b13c92e13b80'
  - url: 'https://git.kernel.org/stable/c/3e07ea9579dc9553d2285c26c2823931358aa3b8'
  - url: 'https://git.kernel.org/stable/c/02558c86b6b761063e9399e6b939984500327ef1'
  - url: 'https://git.kernel.org/stable/c/b9800d7953d119bcc068c74587d48e4ba0313629'
  - url: 'https://git.kernel.org/stable/c/22b8fbded65b8c441b634a185f8da67657df6c50'
tags:
  - cve.org
epss: 0.0019
epssPercentile: 0.07696
ingestedAt: '2026-09-14T15:23:07.456Z'
---

## Overview

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

RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe

get_srq_wqe() reads wqe->dma.num_sge from the shared receive queue
buffer, which is mapped into userspace. It validates num_sge against
max_sge, but then re-reads the same field to calculate the memcpy
size. A concurrent userspace thread can modify num_sge between
validation and use, causing a heap buffer overflow when copying the
WQE into qp->resp.srq_wqe.

Read num_sge into a local variable and use it for both the bounds
check and the size calculation.

## Affected

- `Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < c8db0e5ab0b6c540214c46c56aaac7cbcb0967fe`
- `Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < e48daa94ad2d406225b73491fc935064716f0ec7`
- `Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < 3cfa2a3adc51b7c57729961a03446962ff10e3d2`
- `Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < cd19a6345e3727adafafa5954b58b13c92e13b80`
- `Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < 3e07ea9579dc9553d2285c26c2823931358aa3b8`
- `Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < 02558c86b6b761063e9399e6b939984500327ef1`
- `Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < b9800d7953d119bcc068c74587d48e4ba0313629`
- `Linux >= 8700e3e7c4857d28ebaa824509934556da0b3e76 < 22b8fbded65b8c441b634a185f8da67657df6c50`
- `Linux 4.8`

## Remediation

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