Vulnerability · Published Apr 7, 2026 · Assigned by GitHub_M

CVE-2026-39312Pre-Auth EAP-TLS DoS on SoftEther VPN Developer Edition

High 7.5

In plain English

A high-severity security flaw in SoftEtherVPN from SoftEtherVPN. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.5%top 59.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
SoftEtherVPN	SoftEtherVPN	<= 5.2.5188

Weakness: CWE-789 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/SoftEtherVPN/SoftEtherVPN/security/advisories/GHSA-q5g3-qhc6-pr3h x_refsource_CONFIRM