CVE-2021-20039

CVSS 3.1: 8.8 high
EPSS: 79%p100
Published: Dec 8, 2021 · Dec 8, 2021
Modified: Jun 17, 2026

Analyze CVE-2021-20039 with Vani AIImpact, affected versions, exploitation status, mitigations and detection

Description · NVD

Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

Vendors: sonicwall

Products: sma 200 firmware, sma 210 firmware, sma 410 firmware, sma 400 firmware, sma 500v firmware

Weakness: CWE-78

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

NVD CVE.org GitHub PoCs EPSS (78.7%)

In the news

7 stories

SonicWall SMA devices persistently infected with stealthy OVERSTEP backdoor and rootkit

Help Net SecurityAug 5, 15:29 UTC · Aug 5, 2025MalwareCVE-2021-20035 CVE-2021-20039 CVE-2024-38475+11

UNC6148 Backdoors Fully-Patched SonicWall SMA 100 Series Devices with OVERSTEP Rootkit

The Hacker NewsJul 26, 11:34 UTC · Jul 26, 2025VulnerabilityCVE-2021-20035 CVE-2021-20038 CVE-2021-20039+21 · 1 read

SonicWall customers hit by fresh, ongoing attacks targeting fully patched SMA 100 devices

CyberScoopJul 16, 17:52 UTC · Jul 16, 2025VulnerabilityExploitedCVE-2021-20038 CVE-2024-38475 CVE-2021-20035+21 · 1 read

Description · NVD

In the news

SonicWall SMA devices persistently infected with stealthy OVERSTEP backdoor and rootkit

UNC6148 Backdoors Fully-Patched SonicWall SMA 100 Series Devices with OVERSTEP Rootkit

SonicWall customers hit by fresh, ongoing attacks targeting fully patched SMA 100 devices

Google spots tailored backdoor malware aimed at SonicWall appliances

Google finds custom backdoor being installed on SonicWall network devices

SonicWall Urges Customers to Immediately Patch Critical SMA 100 Flaws

SonicWall strongly urges customers to apply patches to SMA 100 devices