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CVE-2021-20021: SonicWall Email Security Improper Privilege Management Vulnerability

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: yes — in CISA KEV since 2021-11-03
• EPSS: 88.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-04-09 · updated 2026-08-12
• Weakness: CWE-269

Description

A vulnerability in the SonicWall Email Security version 10.0.9.x allows an attacker to create an administrative account by sending a crafted HTTP request to the remote host.

Affected products

• SonicWall Email Security: before 10.0.9.6103 — fixed in 10.0.9.6103
• SonicWall Email Security Appliance 3300 Firmware: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Email Security Appliance 4300 Firmware: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Email Security Appliance 5000 Firmware: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Email Security Appliance 5050 Firmware: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Email Security Appliance 7000 Firmware: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Email Security Appliance 7050 Firmware: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Email Security Appliance 8300 Firmware: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Email Security Appliance 9000 Firmware: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Email Security Virtual Appliance: before 10.0.9.6105 — fixed in 10.0.9.6105
• SonicWall Hosted Email Security: before 10.0.9.6103 — fixed in 10.0.9.6103

How to fix

Upgrade to a fixed version: SonicWall Email Security 10.0.9.6103; SonicWall Email Security Appliance 3300 Firmware 10.0.9.6105; SonicWall Email Security Appliance 4300 Firmware 10.0.9.6105; SonicWall Email Security Appliance 5000 Firmware 10.0.9.6105; SonicWall Email Security Appliance 5050 Firmware 10.0.9.6105; SonicWall Email Security Appliance 7000 Firmware 10.0.9.6105; SonicWall Email Security Appliance 7050 Firmware 10.0.9.6105; SonicWall Email Security Appliance 8300 Firmware 10.0.9.6105; SonicWall Email Security Appliance 9000 Firmware 10.0.9.6105; SonicWall Email Security Virtual Appliance 10.0.9.6105; SonicWall Hosted Email Security 10.0.9.6103. Check the vendor advisory for mitigations.

References

• https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0007
• https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0007
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20021

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