---
id: "CVE-2021-20023"
kind: "vulnerability"
aliases: ["CVE-2021-20023"]
title: "SonicWall SonicWall Email Security: SonicWall Email Security Path Traversal Vulnerability"
severity: "high"
cvss: 4.9
epss: 0.51689
exploited: true
status: "open"
category: "vendor"
products: [{"name": "SonicWall SonicWall Email Security", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["email-security", "exploited", "ransomware", "self-hosted", "sonicwall", "vendor"]
not_affected_if: ["unknown"]
published_at: "2021-04-20T12:15:12+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:34+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-20023", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-20023", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-20023", "first_seen_at": "2026-10-23T21:57:34+00:00"}]
---

# SonicWall SonicWall Email Security: SonicWall Email Security Path Traversal Vulnerability

SonicWall Email Security has a path traversal flaw that lets a logged-in attacker read arbitrary files on the server. Attackers have used it in a chain with CVE-2021-20021 and CVE-2021-20022 to escalate privileges.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:SonicWall SonicWall Email Security affected ? fixed ?

## Fix

Apply the vendor update per SonicWall instructions; exact fixed version not stated in sources.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-20023
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-20023
- 2026-10-23T21:57:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-20023

## From the sources

SonicWall Email Security contains a path traversal vulnerability that allows a post-authenticated attacker to read files on the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20021 and CVE-2021-20022 to achieve privilege escalation.

CISA required action: Apply updates per vendor instructions.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_