CVE-2021-20019

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-06-23 · updated 2026-06-17
Weakness: CWE-200

Description

A vulnerability in SonicOS where the HTTP server response leaks partial memory by sending a crafted HTTP request, this can potentially lead to an internal sensitive data disclosure vulnerability.

Affected products

SonicWall SonicOS: from 7.0.0 before 7.0.0.376; from 7.0.1 before 7.0.1-r1036; 6.0.5.3-94o, 6.5.1.12-3n, 6.5.4.7-83n — fixed in 7.0.0.376, 7.0.1-r1036
SonicWall SonicOSv: 6.5.4.4-44v-21-955

How to fix

Upgrade to a fixed version: SonicWall SonicOS 7.0.0.376, 7.0.1-r1036. Check the vendor advisory for mitigations.

References

https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0006
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0006

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