Threats / SonicWall / CVE-2021-20023
CVE-2021-20023
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
SonicWall Email Security vulnerability
SonicWall Email Security contains a path traversal vulnerability allowing authenticated attackers to read arbitrary files, exploited in ransomware campaigns via a multi-CVE chain for privilege escalation.
Verdict
Today item, not a backlog item.
Post-authenticated path traversal in SonicWall Email Security enables file disclosure and serves as part of a known exploit chain for privilege escalation. Active exploitation in ransomware operations confirms real-world threat.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
9 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 0.51407 — 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-22 Path Traversal — 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 gain initial access to SonicWall Email Security as an authenticated user.
Business
Attacker establishes foothold within email security infrastructure.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I exploit the path traversal flaw to read sensitive configuration and system files on the host.
Business
Confidential data and system details are exposed to the attacker.
3
Lateral reach — past segmentation narrative 3
Attacker
I combine this disclosure with CVE-2021-20021 and CVE-2021-20022 to escalate privileges on the system.
Business
Attacker gains administrative control of the email security appliance.
4
Data at risk — exfiltration narrative 4
Attacker
I use elevated privileges to deploy ransomware or establish persistent access.
Business
Organization faces encryption of critical systems and operational disruption.
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