Threats / SonicWall / CVE-2021-20022
CVE-2021-20022
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
SonicWall Email Security vulnerability
SonicWall Email Security allows post-authenticated attackers to upload dangerous file types, enabling privilege escalation when chained with other vulnerabilities in active exploitation.
Verdict
Today item, not a backlog item.
An authenticated attacker can upload malicious files to SonicWall Email Security systems. This vulnerability is actively exploited in the wild as part of multi-stage attack chains leading to privilege escalation and ransomware deployment.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
7 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.16509 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: SonicWall, SonicWall Email Security. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-434 Unrestricted File Upload — weakness family: Path traversal / file.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I authenticate to the Email Security appliance using valid credentials or a compromised account.
Business
Legitimate user accounts or service credentials are exposed or compromised, creating an entry point.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I upload a malicious file bypassing type restrictions to establish persistence or execute code.
Business
Attackers gain ability to place executable or script content on trusted infrastructure.
3
Lateral reach — past segmentation narrative 3
Attacker
I chain this upload with CVE-2021-20021 and CVE-2021-20023 to escalate privileges on the system.
Business
Attackers achieve administrative control of the email security gateway, a critical network chokepoint.
4
Data at risk — exfiltration narrative 4
Attacker
I deploy ransomware or lateral movement tools across the network from the compromised appliance.
Business
Organization experiences widespread encryption of data, email disruption, and operational shutdown.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05