CVE-2026-39312: SoftEtherVPN is a an open-source cross-platform multi-protocol VPN Program

Q: How do I fix CVE-2026-39312?

softethervpn: upgrade to newer than 5.2.5188. Exact commands for each OS are on this page.

Q: Is CVE-2026-39312 being exploited?

CVE-2026-39312 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-39312 affect?

CVE-2026-39312 affects softethervpn. Severity is high (CVSS 7.5). 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 Dev

Q: How urgent is CVE-2026-39312?

Priority 46/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-39312 is a high-severity flaw (CVSS 7.5) affecting softethervpn. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 61%)
CISA exploited list	No
Weakness	CWE-789
Published	2026-04-07
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: softether

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-07 17:16 UTCPublished CVE record published
2026-06-17 10:41 UTCUpdated Record last modified

softether softethervpn UPGRADE

Affected: <= 5.2.5188

Fixed in: newer than 5.2.5188

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy softethervpn || rpm -q softethervpn || softethervpn --version

2. UPGRADE to newer than 5.2.5188 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade softethervpn

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade softethervpn

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-39312?

softethervpn: upgrade to newer than 5.2.5188. Exact commands for each OS are on this page.

Is CVE-2026-39312 being exploited?

CVE-2026-39312 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-39312 affect?

CVE-2026-39312 affects softethervpn. Severity is high (CVSS 7.5). 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 Dev

How urgent is CVE-2026-39312?

Priority 46/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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