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CVE-2021-20023

80
FAUCET Score

CVE-2021-20023 is a post-authentication arbitrary file read vulnerability affecting SonicWall Email Security version 10.0.9.x. This flaw allows an authenticated attacker to read any file on the remote host. While rated Medium severity (CVSS 4.9), its high EPSS score and FAUCET Risk Score of 99/100 indicate significant real-world danger. This vulnerability is actively exploited in the wild, notably by ransomware campaigns, and has garnered substantial community discussion and media coverage, despite no public exploit code being readily available.

Impacted Technologies

VendorProductVersion(s)CPE
< 10.0.9.6173CPE matchmatch criteria
cpe:2.3:a:sonicwall:email_security:*:*:*:*:*:*:*:*
< 10.0.9.6177CPE matchmatch criteria
cpe:2.3:o:sonicwall:email_security_appliance_9000_firmware:*:*:*:*:*:*:*:*
< 10.0.9.6177CPE matchmatch criteria
cpe:2.3:o:sonicwall:email_security_appliance_3300_firmware:*:*:*:*:*:*:*:*
< 10.0.9.6177CPE matchmatch criteria
cpe:2.3:o:sonicwall:email_security_appliance_4300_firmware:*:*:*:*:*:*:*:*
< 10.0.9.6177CPE matchmatch criteria
cpe:2.3:o:sonicwall:email_security_appliance_8300_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.9MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
1.2
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
50.23%
Probability of exploitation in next 30 days
EPSS Percentile
98.8%
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 0.5023 is in the 100th percentile among its peer group of 3,565 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 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-2021-0010
Vendor Advisory