What is the CVSS score of CVE-2021-20023?

CVE-2021-20023 has a CVSS 3.1 base score of 4.9 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 51.4%.

Is CVE-2021-20023 being actively exploited?

Yes, CVE-2021-20023 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild exploitation. Immediate patching is required.

Email Security Appliance 5000 Firmware CVE-2021-20023

MEDIUM

Path Traversal (CWE-22)

2021-04-20 PSIRT@sonicwall.com

Path Traversal Sonicwall Email Security Appliance 5000 Firmware Email Security Appliance 5050 Firmware Email Security Appliance 7000 Firmware Email Security Appliance 7050 Firmware Email Security Appliance 9000 Firmware Email Security Email Security Virtual Appliance Email Security Appliance 3300 Firmware Email Security Appliance 4300 Firmware Email Security Appliance 8300 Firmware Hosted Email Security

4.9

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

4.9 MEDIUM

AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Added to CISA KEV

Jul 14, 2026 - 04:22 CISA

CVE Published

Apr 20, 2021 - 12:15 nvd

MEDIUM 4.9

DescriptionNVD

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

AnalysisAI

SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to read an arbitrary file on the remote host. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

Technical ContextAI

This vulnerability is classified as Path Traversal (CWE-22), which allows attackers to access files and directories outside the intended path. SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to read an arbitrary file on the remote host. Affected products include: Sonicwall Email Security, Sonicwall Email Security Appliance 9000 Firmware, Sonicwall Email Security Appliance 3300 Firmware, Sonicwall Email Security Appliance 4300 Firmware, Sonicwall Email Security Appliance 8300 Firmware. Version information: version 10.0.9..

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate and canonicalize file paths. Use chroot or sandboxing. Reject input containing path separators or '../' sequences.