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VulnerabilityPublished

CVE-2025-40600: SonicWall SonicOS · Use of Externally-Controlled Format String

Affects SonicWall SonicOSSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.9% chance of exploitation in 30 days – higher than 60% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Jul 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

AI-suggested

Immediate mitigation should focus on reducing exposure of the SonicOS SSL VPN interface to untrusted networks. Organizations should restrict access to the VPN interface using network segmentation, firewall rules, and VPN gateway access control lists to allow connections only from trusted IP ranges. Enabling multi-factor authentication (MFA) and monitoring VPN access logs for anomalous activity can help detect exploitation attempts. Administrators should disable or limit SSL VPN services if feasible until a vendor patch is released. Applying virtual patching via intrusion prevention systems (IPS) or web application firewalls (WAF) that can detect and block format string attack patterns is recommended. Regular backups of device configurations and rapid incident response plans should be in place to restore services quickly if disruption occurs. Organizations should closely monitor SonicWall advisories for patch releases and apply updates promptly once available. Additionally, conducting internal vulnerability assessments and penetration testing focused on VPN infrastructure can help identify and remediate related weaknesses.

Description

Use of Externally-Controlled Format String vulnerability in the SonicOS SSL VPN interface allows a remote unauthenticated attacker to cause service disruption.

References

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