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CVE-2021-20022

64
FAUCET Score

CVE-2021-20022 is a critical vulnerability in SonicWall Email Security version 10.0.9.x that allows a post-authenticated attacker to upload arbitrary files to the remote host. With a CVSS score of 7.2 (HIGH), this flaw presents a significant risk, enabling high impact to confidentiality, integrity, and availability. The vulnerability is actively exploited in the wild, notably by the HelloKitty ransomware, and has garnered substantial community discussion and media coverage, despite a lack of public exploit code.

Impacted Technologies

VendorProductVersion(s)CPE
< 10.0.9.6103CPE matchmatch criteria
cpe:2.3:a:sonicwall:email_security:*:*:*:*:*:*:*:*
< 10.0.9.6105CPE matchmatch criteria
cpe:2.3:o:sonicwall:email_security_appliance_9000_firmware:*:*:*:*:*:*:*:*
< 10.0.9.6105CPE matchmatch criteria
cpe:2.3:o:sonicwall:email_security_appliance_3300_firmware:*:*:*:*:*:*:*:*
< 10.0.9.6105CPE matchmatch criteria
cpe:2.3:o:sonicwall:email_security_appliance_4300_firmware:*:*:*:*:*:*:*:*
< 10.0.9.6105CPE matchmatch criteria
cpe:2.3:o:sonicwall:email_security_appliance_8300_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.2HIGH

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.2
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
16.51%
Probability of exploitation in next 30 days
EPSS Percentile
96.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Added to KEV · Nov 3, 2021
This CVE's current EPSS score of 0.1651 is in the 95th percentile among its peer group of 5,531 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.3 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
psirt.global.sonicwall.com / vuln-detail/SNWLID-2021-0008
Vendor Advisory