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

Vulnerability summary

CVE-2021-20023 is a medium (CVSS 4.9) Path Traversal vulnerability in SonicWall SonicWall Email Security. It is known to be exploited: CISA lists it, first on 03-11-2021. It has been used in ransomware campaigns. EPSS estimates a 51.69% chance of exploitation in the next 30 days, higher than 98.9% of scored vulnerabilities.

Timeline

1. 20-04-2021
   PublishedVulnerability first disclosed.
2. 03-11-2021
   Added to CISA KEVSonicWall Email Security Path Traversal Vulnerability
3. 17-11-2021
   CISA remediation dueApply updates per vendor instructions.
4. 01-10-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.