CVE-2021-20023VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2021-20023: SonicWall Email Security Path Traversal Vulnerability

Affects SonicWall SonicWall Email SecuritySource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 11/03/2021
KEV deadline: 11/17/2021
Ransomware: Used in ransomware campaigns
EPSS: 51.7% chance of exploitation in 30 days – higher than 98% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-20023 (opens in a new tab)

Description

CVE-2021-20023 is a path traversal vulnerability in SonicWall Email Security that allows an authenticated attacker to read arbitrary files on the affected system. This vulnerability has been observed in active exploit chains combined with other SonicWall Email Security vulnerabilities to escalate privileges. It is classified as high severity due to its impact and known exploitation in the wild.

Summary

SonicWall Email Security contains a path traversal vulnerability (CWE-22) that enables a post-authenticated attacker to read files on the remote host. This vulnerability is part of an exploit chain with CVE-2021-20021 and CVE-2021-20022, which together facilitate privilege escalation on the affected system. The vulnerability has been exploited in the wild and is known to be used in ransomware campaigns.

Impact

An attacker with authentication can leverage this vulnerability to access arbitrary files on the SonicWall Email Security appliance, potentially exposing sensitive information. When combined with other vulnerabilities in the exploit chain, it can lead to privilege escalation, increasing the attacker's control over the system. This poses a significant risk to confidentiality and system integrity.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict access to the SonicWall Email Security management interface to trusted users only and monitor for suspicious activity. Follow SonicWall's official advisories for updates on patches or mitigations.

Weaknesses

CWE-22Path Traversal (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 08:55:32 UTC

Weaknesses

References

Related threats