CVE-2021-20021VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2021-20021: SonicWall Email Security Improper Privilege Management 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: 88.8% chance of exploitation in 30 days – higher than 99% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-20021 (opens in a new tab)

Description

CVE-2021-20021 is an improper privilege management vulnerability in SonicWall Email Security that allows attackers to create an administrative account via a crafted HTTP request. This vulnerability is part of an exploit chain with CVE-2021-20022 and CVE-2021-20023 used for privilege escalation. It has been exploited in the wild and is associated with known ransomware campaigns.

Summary

SonicWall Email Security contains a vulnerability (CWE-306) involving improper privilege management, enabling an attacker to create an administrative account by sending a specially crafted HTTP request to the affected system. This vulnerability is used in conjunction with CVE-2021-20022 and CVE-2021-20023 in an exploit chain to escalate privileges. The vulnerability has been observed in active exploitation scenarios, including ransomware campaigns.

Impact

Successful exploitation allows an attacker to gain administrative privileges on SonicWall Email Security systems by creating an administrative account remotely. This can lead to full control over the affected system and facilitate further malicious activities such as ransomware deployment.

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 management interface and monitor for suspicious HTTP requests that could indicate exploitation attempts.

Weaknesses

CWE-306Missing Authentication for Critical Function (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 08:55:40 UTC

Weaknesses

References

Related threats