Vulnerability in SonicWall Gen7 firewalls enables remote Denial-of-Service attacks
Take action: If you have SonicWall Gen7 firewalls, check the advisory and your OS versions. If they are vulnerable, plan an update to SonicOS version 7.3.0-7012 or higher. The main risk is attackers crashing your system and making your VPN useless. If you can't update right away, disable the SSL-VPN interface, since it won't be of much use if attackers are crashing it.
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SonicWall is reporting a vulnerability affecting the SSL VPN interface of its Gen7 firewall products that could allow remote unauthenticated attackers to cause service disruptions through denial-of-service attacks.
The vulnerability is tracked as CVE-2025-40600 (CVSS score varies from 5.9 to 9.8) and is a Use of Externally-Controlled Format String vulnerability, which occurs when user-controllable input is unsafely incorporated into format strings in printf-style functions.
The vulnerability allows remote unauthenticated attackers to cause memory corruption and subsequent service crashes. The attack complexity is considered high, but it can be executed remotely and without authentication.
The vulnerability affects SonicWall Gen7 products running vulnerable firmware versions TZ270, TZ270W, TZ370, TZ370W, TZ470, TZ470W, TZ570, TZ570W, TZ570P, TZ670, NSa 2700, NSa 3700, NSa 4700, NSa 5700, NSa 6700, NSsp 10700, NSsp 11700, NSsp 13700, and NSsp 15700 models. Additionally, Gen7 virtual firewalls (NSv) are also affected, including NSV270, NSv470, and NSv870 variants deployed across ESX, KVM, HYPER-V, AWS, and Azure platforms.
Systems running SonicOS versions 7.2.0-7015 and older are vulnerable to this attack, but the 7.0.1 branch is not affected.
SonicWall's Gen6 and Gen8 firewalls, as well as SMA 1000 and SMA 100 series SSL VPN products, are not impacted by this specific vulnerability, limiting the scope to Gen7 products only.
SonicWall has released patched software version 7.3.0-7012 and higher versions to address this security issue. Organizations should prioritize upgrading to the patched version to maintain both security and SSL VPN functionality. For organizations unable to immediately implement the software update, SonicWall recommends disabling the SSL-VPN interface as a temporary workaround.
