---
id: CVE-2021-20023
title: >-
  SonicWall Email Security version 10.0.9.x contains a vulnerability that allows
  a post-authenticated attacker to read an arbitrary file on the remote host.
summary: >-
  SonicWall Email Security version 10.0.9.x contains a vulnerability that allows
  a post-authenticated attacker to read an arbitrary file on the remote host.
severity: medium
cvss: 4.9
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-22
  - CWE-22
vendor: sonicwall
product: email_security
affected:
  - email_security < 10.0.9.6173
  - email_security_appliance_9000_firmware < 10.0.9.6177
  - email_security_appliance_3300_firmware < 10.0.9.6177
  - email_security_appliance_4300_firmware < 10.0.9.6177
  - email_security_appliance_8300_firmware < 10.0.9.6177
  - email_security_appliance_5000_firmware < 10.0.9.6177
  - email_security_appliance_7000_firmware < 10.0.9.6177
  - email_security_appliance_5050_firmware < 10.0.9.6177
  - email_security_appliance_7050_firmware < 10.0.9.6177
  - email_security_virtual_appliance < 10.0.9.6177
  - hosted_email_security < 10.0.9.6173
patched:
  - email_security 10.0.9.6173
  - email_security_appliance_9000_firmware 10.0.9.6177
  - email_security_appliance_3300_firmware 10.0.9.6177
  - email_security_appliance_4300_firmware 10.0.9.6177
  - email_security_appliance_8300_firmware 10.0.9.6177
  - email_security_appliance_5000_firmware 10.0.9.6177
  - email_security_appliance_7000_firmware 10.0.9.6177
  - email_security_appliance_5050_firmware 10.0.9.6177
  - email_security_appliance_7050_firmware 10.0.9.6177
  - email_security_virtual_appliance 10.0.9.6177
  - hosted_email_security 10.0.9.6173
published: '2021-04-20'
updated: '2026-08-12'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-20023'
references:
  - url: 'https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010'
    label: PSIRT@sonicwall.com
  - url: 'https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20023
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - kev
  - in-the-wild
epss: 0.51407
epssPercentile: 0.98904
kev: true
kevDateAdded: '2021-11-03'
kevDueDate: '2021-11-17'
kevRansomware: true
exploited: true
zeroDay: true
ingestedAt: '2026-08-12T19:54:25.950Z'
---

## Overview

SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to read an arbitrary file on the remote host.

## Affected

- `email_security < 10.0.9.6173`
- `email_security_appliance_9000_firmware < 10.0.9.6177`
- `email_security_appliance_3300_firmware < 10.0.9.6177`
- `email_security_appliance_4300_firmware < 10.0.9.6177`
- `email_security_appliance_8300_firmware < 10.0.9.6177`
- `email_security_appliance_5000_firmware < 10.0.9.6177`
- `email_security_appliance_7000_firmware < 10.0.9.6177`
- `email_security_appliance_5050_firmware < 10.0.9.6177`
- `email_security_appliance_7050_firmware < 10.0.9.6177`
- `email_security_virtual_appliance < 10.0.9.6177`
- `hosted_email_security < 10.0.9.6173`

## Remediation

Upgrade past the affected range:

- `email_security 10.0.9.6173`
- `email_security_appliance_9000_firmware 10.0.9.6177`
- `email_security_appliance_3300_firmware 10.0.9.6177`
- `email_security_appliance_4300_firmware 10.0.9.6177`
- `email_security_appliance_8300_firmware 10.0.9.6177`
- `email_security_appliance_5000_firmware 10.0.9.6177`
- `email_security_appliance_7000_firmware 10.0.9.6177`
- `email_security_appliance_5050_firmware 10.0.9.6177`
- `email_security_appliance_7050_firmware 10.0.9.6177`
- `email_security_virtual_appliance 10.0.9.6177`
- `hosted_email_security 10.0.9.6173`