Security Notice: Critical Arbitrary File Delete Vulnerability in SonicWall SMA 100 Series Appliances

First Published:08/19/2021 Last Updated:09/24/2021

A critical vulnerability (CVSS 9.1) in SMA 100 series appliances, which includes SMA 200, 210, 400, 410 and 500v, could potentially allow a remote unauthenticated attacker the ability to delete arbitrary files from a SMA 100 series appliance and potentially gain administrator access to the device.

The vulnerability (SNWLID-2021-0021) is due to an improper limitation of a file path to a restricted directory potentially leading to arbitrary file deletion as ‘nobody.’

There is no evidence that this vulnerability is being exploited in the wild.

SonicWall strongly urges that organizations follow the guidance below to patch SMA 100 series products, which include SMA 200, 210, 400, 410 and 500v.


As outlined in SNWLID-2021-0021, successfully leveraging CVE-2021-20034 against impacted SMA 100 devices can result in a remote attacker obtaining administrator access on the underlying host. The below SMA 100 series appliances are impacted by this vulnerability.

Impacted Platforms

Impacted Versions


SMA 100 Series
(SMA 200, 210, 400, 410, 500v)


  • and earlier
  • and earlier
  • and earlier



There are no temporary mitigations. SonicWall urges impacted customers to implement applicable patches as soon as possible.


Organizations using SMA 100 series appliances should immediately log in to to upgrade their appliances to the patched firmware versions outlined below. For upgrade assistance, please reference the KB article, “How to Upgrade Firmware on SMA 100 Series Appliances”  or contact SonicWall support.



Impacted Version

Fixed Version











SMA 100 Series










  • SMA 200
  • SMA 210
  • SMA 400
  • SMA 410
  • SMA 500v (ESX, KVM, AWS, Azure)

and earlier


and earlier



and earlier


NOTE: The above SMA 100 series firmware updates also address non-critical vulnerabilities outlined in SNWLID-2021-0020 and SNWLID-2021-0022.

IMPORTANT: Adhering to industry best practices, SonicWall does not provide support (e.g., technical support, firmware updates/upgrades, hardware replacements) for products that have reached End-of-Support (EOS) status, including Secure Remote Access (SRA) series devices. View the SonicWall Product Lifecycle Table for more information.


TIP: See the Japanese translation for this alert here.