CVE-2021-20023

Name: CVE-2021-20023
Creator: NVD / NIST
Published: 2021-04-20T12:15:12.587+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.9/10Actively ExploitedEPSS 51.41%

Last modified Jun 17, 2026

CVE-2021-20023 is a medium-severity vulnerability rated 4.9/10 on the CVSS scale. 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.. CISA has confirmed active exploitation in the wild. EPSS estimates a 51.41% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

4.9/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

51.41%

98.8th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Nov 17, 2021.

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Sonicwall	Email Security	< 10.0.9.6173
Sonicwall	Email Security Appliance 9000 Firmware	< 10.0.9.6177
Sonicwall	Email Security Appliance 3300 Firmware	< 10.0.9.6177
Sonicwall	Email Security Appliance 4300 Firmware	< 10.0.9.6177
Sonicwall	Email Security Appliance 8300 Firmware	< 10.0.9.6177
Sonicwall	Email Security Appliance 5000 Firmware	< 10.0.9.6177
Sonicwall	Email Security Appliance 7000 Firmware	< 10.0.9.6177
Sonicwall	Email Security Appliance 5050 Firmware	< 10.0.9.6177
Sonicwall	Email Security Appliance 7050 Firmware	< 10.0.9.6177
Sonicwall	Email Security Virtual Appliance	< 10.0.9.6177
Sonicwall	Hosted Email Security	< 10.0.9.6173

References

https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010Vendor Advisory
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20023US Government Resource

Timeline

Published: Apr 20, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-20023?

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.

How severe is CVE-2021-20023?

CVE-2021-20023 has a CVSS score of 4.9/10 (MEDIUM severity). The EPSS model estimates a 51.41% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2021-20023?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20023?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST