CVE-2025-40600
Published: May 13, 2026
Official Description
Use of Externally-Controlled Format String vulnerability in the SonicOS SSL VPN interface allows a remote unauthenticated attacker to cause service disruption.
Risk Analysis
This vulnerability in the SonicOS SSL VPN interface, involving the use of externally-controlled format strings, allows a remote unauthenticated attacker to cause service disruption. This can lead to a denial-of-service condition. Its inclusion in CISA's KEV confirms active exploitation, making it an urgent concern.
This vulnerability is remotely exploitable. Active exploitation has been observed in the wild, as indicated by its 'in_the_wild' exploit status and inclusion in CISA's KEV.
To mitigate this, apply the latest security patches and firmware updates for SonicOS SSL VPN. Implement robust input validation and sanitization to prevent format string vulnerabilities.
Technical Analysis
CVE-2025-40600 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2025-40600 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Exploit & PoC Resources
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2025-40600 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1