---
id: "CVE-2021-20021"
kind: "vulnerability"
aliases: ["CVE-2021-20021"]
title: "SonicWall SonicWall Email Security: SonicWall Email Security Improper Privilege Management Vulnerability"
severity: "critical"
cvss: 9.8
epss: 0.8878
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: "2021-04-09T18:15:13+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-2021-20021", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-20021", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-20021", "first_seen_at": "2026-10-23T21:57:34+00:00"}]
---

# SonicWall SonicWall Email Security: SonicWall Email Security Improper Privilege Management Vulnerability

SonicWall Email Security has an improper privilege management flaw that lets an unauthenticated attacker create an administrator account by sending a crafted HTTP request. It is known to be used in a real exploit chain with CVE-2021-20022 and CVE-2021-20023 for privilege escalation.

_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's updates per SonicWall instructions; exact fixed version unknown from sources.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-20021
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-20021
- 2026-10-23T21:57:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-20021

## From the sources

SonicWall Email Security contains an improper privilege management vulnerability that allows an attacker to create an administrative account by sending a crafted HTTP request to the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20022 and CVE-2021-20023 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_