What it is
CVE-2021-20021 is an unauthenticated vulnerability affecting 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...
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2021-20021
Email Security
SonicWall / Email Security · 10.0.9 and earlier
- Severity
- CVSS 9.8 · Critical
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 83.4%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.
Who is affected?
SonicWall / Email Security 10.0.9 and earlier.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
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.
Vendor
Product
Affected
Status
SonicWall
Email Security
10.0.9 and earlier
Affected
- Published
- 09 Apr 2021
- Exploitation Reported
- 03 Nov 2021
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
nuclei_scanner
edge
cisa
malware
ransomware
CVE References
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0007 psirt.global.sonicwall.com · CVE Record https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0007
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CISA
Independent exploitation attestation added to the KEV Intelligence record.
Used in malware
CISA
Malware families have been linked to exploitation of this CVE.
Proof of concept available
GitHub
Public scanner or PoC coverage increases practical exploitability.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2021-11-03 00:00 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
Nuclei template detected 01 Jun 2026.
View Nuclei template (opens in new tab)Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →Scanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-20021.yaml | 01 Jun 2026 |
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
9.8
Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
83.4%
Weaknesses
All CVSS Scores
CVSS v3.1
9.8
Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v2.0
7.5
High
AV:N/AC:L/Au:N/C:P/I:P/A:P
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
SUPRAAA-1337/CVE-2021-20021
github · Created 2023-09-07 16:17:41 UTC · 2 stars
SonicWall Email Security <= 10.0.9.x - Unauthenticated Admin Account Creation
nuclei · Created Unknown
Timeline
From disclosure to observed exploitation
-
Nuclei template available
Scanner coverage available
-
Public PoC available
Public proof-of-concept code published
-
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
First public exploitation report
Exploit observed in malware
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2021-20021
Free JSON includes basic KEV fields{
"cve_id": "CVE-2021-20021",
"confidence": "Confirmed",
"cvss_score": 9.8,
"epss_score": 0.83425,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}