CVE-2020-5135: SonicWall SonicOS Buffer Overflow Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2022-03-15. EPSS: 26.9% chance of exploitation in the next 30 days.

A buffer overflow vulnerability in SonicOS allows a remote attacker to cause Denial of Service (DoS) and potentially execute arbitrary code by sending a malicious request to the firewall. This vulnerability affected SonicOS Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version 7.0.0.0.

Affected products

• SonicWall SonicOS: up to and including 6.0.5.3; from 6.5.0.0, up to and including 6.5.1.11; from 6.5.4.0, up to and including 6.5.4.7; version 7.0.0.0 only
• SonicWall Sonicosv: up to and including 6.5.4.4

Published 2020-10-12. Last modified 2026-06-17.