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CVE-2021-20023

SonicWall Email Security Path Traversal

4.9 MEDIUMActively exploited (CISA KEV)Used in ransomwareEPSS 51.7%
  1. Published20 Apr 2021
  2. Added to CISA KEV3 Nov 2021
  3. Remediation due17 Nov 2021
Actively exploited (CISA KEV)

SonicWall Email Security contains a path traversal vulnerability that allows a post-authenticated attacker to read files on the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20021 and CVE-2021-20022 to achieve privilege escalation.

Added to KEV: 3 Nov 2021Federal remediation due: 17 Nov 2021Used in ransomware

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredHigh
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Affected products

SonicWall Email Security< 10.0.9.6173
SonicWall Email Security Virtual Appliance< 10.0.9.6177
SonicWall Hosted Email Security< 10.0.9.6173
SonicWall Email Security Appliance 3300 Firmware< 10.0.9.6177
SonicWall Email Security Appliance 4300 Firmware< 10.0.9.6177
SonicWall Email Security Appliance 5000 Firmware< 10.0.9.6177
SonicWall Email Security Appliance 5050 Firmware< 10.0.9.6177
SonicWall Email Security Appliance 7000 Firmware< 10.0.9.6177
SonicWall Email Security Appliance 7050 Firmware< 10.0.9.6177
SonicWall Email Security Appliance 8300 Firmware< 10.0.9.6177
SonicWall Email Security Appliance 9000 Firmware< 10.0.9.6177

Remediation

Fixed in
SonicWall Email Security≥ 10.0.9.6173
SonicWall Email Security Virtual Appliance≥ 10.0.9.6177
SonicWall Hosted Email Security≥ 10.0.9.6173
SonicWall Email Security Appliance 3300 Firmware≥ 10.0.9.6177
SonicWall Email Security Appliance 4300 Firmware≥ 10.0.9.6177
SonicWall Email Security Appliance 5000 Firmware≥ 10.0.9.6177
SonicWall Email Security Appliance 5050 Firmware≥ 10.0.9.6177
SonicWall Email Security Appliance 7000 Firmware≥ 10.0.9.6177
SonicWall Email Security Appliance 7050 Firmware≥ 10.0.9.6177
SonicWall Email Security Appliance 8300 Firmware≥ 10.0.9.6177

References

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Frequently asked

Is CVE-2021-20023 being actively exploited?

Yes. CVE-2021-20023 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021. It has been used in ransomware campaigns.

How severe is CVE-2021-20023?

CVE-2021-20023 has a CVSS 3.1 base score of 4.9, rated medium. EPSS estimates a 51.7% probability of exploitation.

Which products are affected by CVE-2021-20023?

Affected products include SonicWall Email Security, SonicWall Email Security Virtual Appliance, SonicWall Hosted Email Security, SonicWall Email Security Appliance 3300 Firmware, SonicWall Email Security Appliance 4300 Firmware, and 6 more.

How do I fix CVE-2021-20023?

Upgrade affected software to a fixed version, for example SonicWall Email Security 10.0.9.6173, SonicWall Email Security Virtual Appliance 10.0.9.6177, SonicWall Hosted Email Security 10.0.9.6173 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-20023 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.