EUVD-2026-19804
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
3Tags
Description
SoftEtherVPN is a an open-source cross-platform multi-protocol VPN Program. In 5.2.5188 and earlier, a pre-authentication denial-of-service vulnerability exists in SoftEther VPN Developer Edition 5.2.5188 (and likely earlier versions of Developer Edition). An unauthenticated remote attacker can crash the vpnserver process by sending a single malformed EAP-TLS packet over raw L2TP (UDP/1701), terminating all active VPN sessions.
Analysis
Remote unauthenticated denial-of-service in SoftEther VPN Developer Edition 5.2.5188 and earlier allows attackers to crash the vpnserver process and terminate all active VPN sessions by sending a single malformed EAP-TLS packet over raw L2TP (UDP port 1701). This pre-authentication vulnerability requires no privileges or user interaction (CVSS vector AV:N/AC:L/PR:N/UI:N), enabling trivial service disruption. …
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Remediation
Within 24 hours: identify all instances of SoftEther VPN Developer Edition 5.2.5188 or earlier in your environment via network scanning and asset inventory. Within 7 days: evaluate upgrade path to SoftEther VPN 5.2.5189 or later if available from vendor, or contact SoftEther development for patch availability and timeline. …
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External POC / Exploit Code
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