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CVE-2021-20023: SonicWall Email Security Path Traversal Vulnerability

• Severity: medium (CVSS 4.9 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2021-11-03
• EPSS: 51.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-04-20 · updated 2026-10-01
• Weakness: CWE-22

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.

Affected products

• SonicWall Email Security: before 10.0.9.6173 — fixed in 10.0.9.6173
• SonicWall Email Security Appliance 3300 Firmware: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Email Security Appliance 4300 Firmware: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Email Security Appliance 5000 Firmware: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Email Security Appliance 5050 Firmware: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Email Security Appliance 7000 Firmware: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Email Security Appliance 7050 Firmware: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Email Security Appliance 8300 Firmware: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Email Security Appliance 9000 Firmware: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Email Security Virtual Appliance: before 10.0.9.6177 — fixed in 10.0.9.6177
• SonicWall Hosted Email Security: before 10.0.9.6173 — fixed in 10.0.9.6173

How to fix

Upgrade to a fixed version: SonicWall Email Security 10.0.9.6173; SonicWall Email Security Appliance 3300 Firmware 10.0.9.6177; SonicWall Email Security Appliance 4300 Firmware 10.0.9.6177; SonicWall Email Security Appliance 5000 Firmware 10.0.9.6177; SonicWall Email Security Appliance 5050 Firmware 10.0.9.6177; SonicWall Email Security Appliance 7000 Firmware 10.0.9.6177; SonicWall Email Security Appliance 7050 Firmware 10.0.9.6177; SonicWall Email Security Appliance 8300 Firmware 10.0.9.6177; SonicWall Email Security Appliance 9000 Firmware 10.0.9.6177; SonicWall Email Security Virtual Appliance 10.0.9.6177; SonicWall Hosted Email Security 10.0.9.6173. Check the vendor advisory for mitigations.

References

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

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