CVE-2021-20021
SonicWall Email Security Improper Privilege Management Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
A vulnerability in the SonicWall Email Security version 10.0.9.x allows an attacker to create an administrative account by sending a crafted HTTP request to the remote host.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 88.78% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 3 November 2021 · due 17 November 2021 · used in ransomware campaigns
- Weakness
- CWE-269
- Affected
- 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 · sonicwall/email security appliance 5000 firmware · sonicwall/email security appliance 7000 firmware · sonicwall/email security appliance 5050 firmware · sonicwall/email security appliance 7050 firmware · sonicwall/email security virtual appliance · sonicwall/hosted email security
- Source
- PSIRT@sonicwall.com
EPSS moved from 88.7% on 24 September 2026 to 88.8% on 30 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-20021
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.