How severe is CVE-2026-39312?

CVE-2026-39312 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-39312 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39312?

CVE-2026-39312 affects Softether Softethervpn. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39312?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-39312 have an EU (EUVD) identifier?

Yes. CVE-2026-39312 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19804.

When was CVE-2026-39312 published?

CVE-2026-39312 was published on 2026-04-07 and last updated on 2026-06-17.

CVE-2026-39312

CVE-2026-39312 is a high-severity vulnerability in Softether Softethervpn with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-789.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-19804
Weakness: CWE-789
Affected product: Softether Softethervpn
Published: 2026-04-07
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-39312?: 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.
How severe is CVE-2026-39312?: CVE-2026-39312 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-39312 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39312?: CVE-2026-39312 affects Softether Softethervpn. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39312?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-39312 have an EU (EUVD) identifier?: Yes. CVE-2026-39312 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19804.
When was CVE-2026-39312 published?: CVE-2026-39312 was published on 2026-04-07 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:a:softether:softethervpn:*:*:*:*:developer:*:*:*

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