PatchTheCVECVE-2021-20021: SonicWall Email Security Improper Privilege Management Vulnerability
CVE-2021-20021 is a critical-severity flaw (CVSS 9.8) affecting email security, email security appliance 9000 firmware, email security appliance 3300 firmware, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- Critical severity
- EPSS top 1%: very likely to be exploited
- Exploited in the wild (CISA KEV)
- Used in ransomware campaigns
- CISA SSVC: automatable with total technical impact
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 88.8% (top 1%) |
| CISA exploited list | Yes, fix due 2021-11-17, used in ransomware |
| Weakness | CWE-269 |
| Published | 2021-04-09 |
| Last modified | 2026-08-12 |
Last updated 2026-08-12 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Exploited Added to the CISA Known Exploited Vulnerabilities list
- Deadline CISA due date for US federal agencies to patch
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- GitHub PoC: SUPRAAA-1337/CVE-2021-20021 (2 stars)
- Nuclei scan template: SonicWall Email Security <= 10.0.9.x - Unauthenticated Admin Account Creation
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-20021?
email security: upgrade to 10.0.9.6103; email security appliance 9000 firmware: upgrade to 10.0.9.6105; email security appliance 3300 firmware: upgrade to 10.0.9.6105. Exact commands for each OS are on this page.
Is CVE-2021-20021 being exploited?
Yes. CVE-2021-20021 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.
What does CVE-2021-20021 affect?
CVE-2021-20021 affects email security, email security appliance 9000 firmware, email security appliance 3300 firmware. Severity is critical (CVSS 9.8). 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.
How urgent is CVE-2021-20021?
Priority 97/100. Critical severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); Used in ransomware campaigns; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action
Software pages
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