IRONSMITHINTEL
CRITICALCVSS9.8
|
Actively Exploited
|CISA KEV|CVE-2021-20021|Auth: none — unauthenticated|Reboot: required|Manual only

SonicWall SonicWall Email Security < 10.0.9

SonicWall Email Security contains an improper privilege management vulnerability that allows an attacker to create an administrative account by sending a crafted HTTP request to the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20022 and CVE-2021-20023 to achieve privilege escalation.

Published Apr 9, 2021 · Updated May 17, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. CISA has confirmed use of this vulnerability in known ransomware campaigns — treat as high priority for remediation. Federal agencies are required to remediate by 2021-11-17 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Improper Privilege Management (CWE-269) vulnerability in SonicWall SonicWall Email Security. 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. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

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Phishing link

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Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

IT Security
Running email security: v < 10.0.9.6103; email security appliance 9000 firmware: v < 10.0.9.6105; email security appliance 3300 firmware: v < 10.0.9.6105; email security appliance 4300 firmware: v < 10.0.9.6105; email security appliance 8300 firmware: v < 10.0.9.6105; email security appliance 5000 firmware: v < 10.0.9.6105; email security appliance 7000 firmware: v < 10.0.9.6105; email security appliance 5050 firmware: v < 10.0.9.6105; email security appliance 7050 firmware: v < 10.0.9.6105; email security virtual appliance: v < 10.0.9.6105; hosted email security: v < 10.0.9.6103
Fixed in10.0.9
Real-world incidentsWhat we've seen

CISA confirms this CVE has been used in known ransomware campaigns. Added to the KEV catalog on 2021-11-03; federal agencies required to remediate by 2021-11-17.

How to patch

Manual remediation steps

1
Identify affected hosts: query inventory for network-security installs in scope.
2
Upgrade to version 10.0.9 or later. Stage in a test ring before broad deployment.
3
Verify by checking the installed version on a sample of remediated hosts.
4
Document the remediation in your change ticket and re-scan with your vulnerability scanner to confirm closure.
PowerShell automationComing soon

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