---
id: CVE-2023-6693
title: 'Qemu: virtio-net: stack buffer overflow in virtio_net_flush_tx()'
summary: >-
  A stack based buffer overflow was found in the virtio-net device of QEMU. This
  issue occurs when flushing TX in the virtio_net_flush_tx function if guest
  features VIRTIO_NET_F_HASH_REPORT, VIRTIO_F_VERSION_1 and
  VIRTIO_NET_F_MRG_RXBUF ar…
severity: medium
cvss: 4.9
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'
cvssSource: cna
cwe:
  - CWE-121
vendor: Red Hat
product: 'virt-devel:rhel'
affected:
  - 'virt-devel:rhel (all versions)'
  - 'virt:rhel (all versions)'
  - qemu-kvm (all versions)
  - qemu-kvm
  - qemu-kvm
  - qemu-kvm-ma
  - 'virt:av/qemu-kvm (all versions)'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2025-05-21T14:46:00.186400Z'
published: '2024-01-02'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T11:37:29.413Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-6693'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2024:2962'
    label: 'RHSA-2024:2962'
  - url: 'https://access.redhat.com/errata/RHSA-2025:4492'
    label: 'RHSA-2025:4492'
  - url: 'https://access.redhat.com/security/cve/CVE-2023-6693'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2254580'
    label: RHBZ#2254580
tags:
  - cve.org
epss: 0.0033
epssPercentile: 0.26256
ingestedAt: '2026-11-05T21:36:00.811Z'
---

## Overview

A stack based buffer overflow was found in the virtio-net device of QEMU. This issue occurs when flushing TX in the virtio_net_flush_tx function if guest features VIRTIO_NET_F_HASH_REPORT, VIRTIO_F_VERSION_1 and VIRTIO_NET_F_MRG_RXBUF are enabled. This could allow a malicious user to overwrite local variables allocated on the stack. Specifically, the `out_sg` variable could be used to read a part of process memory and send it to the wire, causing an information leak.

## Affected

- `virt-devel:rhel (all versions)`
- `virt:rhel (all versions)`
- `qemu-kvm (all versions)`
- `qemu-kvm`
- `qemu-kvm`
- `qemu-kvm-ma`
- `virt:av/qemu-kvm (all versions)`

## Remediation

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

### Workarounds

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.