CVE Intelligence
CISA KEV High File handling

CVE-2021-20022 — SonicWall Email Security Unrestricted Upload of File Vulnerability

SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to upload an arbitrary file to the remote host.

Published Apr 9, 2021 · Updated Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: sonicwall

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Nov 3, 2021 R used by ransomware (CISA)
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • Used in ransomware campaigns (CISA)+10
  • EPSS 16.6% (30-day exploitation probability)+15
  • Technical severity (high)+6
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Confirmed
CISA KEV, listed Nov 3, 2021
EPSS FIRST
16.64%
ahead of 97% of scored CVEs · Oct 14, 2026
Affects
Sonicwall
Email Security and 10 more
CVSS base
7.2
High · 4 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Active
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

CISA required action CISA

Apply updates per vendor instructions.

US federal deadline: Nov 17, 2021 — passed 1793 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Sonicwall Email Security, Sonicwall Email Security Appliance 3300 Firmware, Sonicwall Email Security Appliance 4300 Firmware…).
  2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. EPSS ahead of 97% of scored CVEs: prioritize it in the patch queue.
  5. Search available logs for exploit probes matching the vulnerability class (file handling), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Sonicwall Email Security < 10.0.9.6103 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security version 10.0.9 and earlier Vulnerable CVE Program (cve.org) e CISA ADP
Sonicwall Email Security Appliance 3300 Firmware < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security Appliance 4300 Firmware < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security Appliance 5000 Firmware < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security Appliance 5050 Firmware < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security Appliance 7000 Firmware < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security Appliance 7050 Firmware < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security Appliance 8300 Firmware < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security Appliance 9000 Firmware < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Email Security Virtual Appliance < 10.0.9.6105 Vulnerable NIST National Vulnerability Database
Sonicwall Hosted Email Security < 10.0.9.6103 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.2 CVSS 3.1 High 1.2 5.9 nvd@nist.gov via NIST National Vulnerability Database
7.2 CVSS 3.1 High 1.2 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
7.2 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
7.2 CVSS 3.1 High — — CISA-ADP via CVE Program (cve.org) e CISA ADP
7.5 CVSS 2.0 High 10.0 6.4 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-434 · Unrestricted Upload of File with Dangerous Type

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed
Nov 3, 2021
Federal deadline
Nov 17, 2021
passed 1793 day(s) ago
Ransomware use
Known

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 16.64%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Monitor file creation in web directories and paths with traversal sequences (../).
  • Hunt retroactively in logs from before Nov 3, 2021 (KEV listing): exploitation may have started earlier.
web/proxy/WAF logsnetwork IDS/IPSfile integrity (FIM)endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · sonicwall/email security
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Affected products added · sonicwall/email security, sonicwall/email security appliance 9000 firmware, sonicwall/email security appliance 3300 firm
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 7.2
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Added to CISA KEV (detected)
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Record created in this database
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • 2021
  • Added to CISA KEV catalog
    Nov 2, 2021 · CISA
  • CVE published
    Apr 9, 2021 · sonicwall

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

Elsewhere on this site

Sonicwall
every CVE for this vendor
2021-11
what else CISA listed that month
File handling
same class
CWE-434
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-3469 Improper Input Validation in Sonicwall Email Security Mar 31, 2026
  • CVE-2026-3470 Improper Input Validation in Sonicwall Email Security Mar 31, 2026
  • CVE-2026-3468 Cross-site Scripting (XSS) in Sonicwall Email Security Mar 31, 2026
  • CVE-2025-40604 Download of Code Without Integrity Check in Sonicwall Email Security Appliance 5000 Firmware Nov 20, 2025
  • CVE-2025-40605 Relative Path Traversal in Sonicwall Email Security Appliance 5000 Firmware Nov 20, 2025
  • CVE-2021-45046 Apache Log4j2 Deserialization of Untrusted Data Vulnerability KEV Dec 14, 2021

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2021-20022 is "SonicWall Email Security Unrestricted Upload of File Vulnerability", rated High. It affects Email Security (Sonicwall); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 7.2 describes technical severity. EPSS 16.64% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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