CVE-2021-20023
SonicWall Email Security Path Traversal Vulnerability
- Medium 4.9
- Exploited: added to CISA KEV 3 Nov 2021
- Used in ransomware campaigns
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.
Key facts
- Published
- 20 Apr 2021
- Last changed
- 1 Oct 2026
- Assigned by
- sonicwall
- KEV added
- 3 Nov 2021
- KEV fix due
- 17 Nov 2021
- Used in ransomware
- Yes, according to CISA
- EPSS
- 51.689% likely to be exploited in the next 30 days, higher than 98.966% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: yes; Technical impact: total
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 4.9CVSS 3.1, Mediumfrom CISA (ADP container)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
What to do
- Apply updates per vendor instructions.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| SonicWall | Email Security |
|
Timeline
- 20 Apr 2021 Published
- 3 Nov 2021 CVE-2021-20023 added to CISA KEV
- 3 Nov 2021 Added to the CISA KEV catalogue
Weakness
Practice this bug class
HackZoneLabs has a hands-on lab on Path traversal (CWE-22).