How severe is CVE-2025-54870?

CVE-2025-54870 has a CVSS 4.0 base score of 8.7, rated high severity.

Is CVE-2025-54870 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-54870?

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-2025-54870 have an EU (EUVD) identifier?

Yes. CVE-2025-54870 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-23579.

When was CVE-2025-54870 published?

CVE-2025-54870 was published on 2025-08-05 and last updated on 2026-06-17.

CVE-2025-54870

CVE-2025-54870 is a high-severity vulnerability with a CVSS 4.0 base score of 8.7. 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-636.

Key facts

Severity: High (CVSS 4.0 base score 8.7)
EPSS exploit prediction: 0% (10th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-23579
Weakness: CWE-636
Published: 2025-08-05
Last modified: 2026-06-17

Description

VTun-ng is a Virtual Tunnel over TCP/IP network. In versions 3.0.17 and below, failure to initialize encryption modules might cause reversion to plaintext due to insufficient error handling. The bug was first introduced in VTun-ng version 3.0.12. This is fixed in version 3.0.18. To workaround this issue, avoid blowfish-256.

Frequently asked questions

What is CVE-2025-54870?: VTun-ng is a Virtual Tunnel over TCP/IP network. In versions 3.0.17 and below, failure to initialize encryption modules might cause reversion to plaintext due to insufficient error handling. The bug was first introduced in VTun-ng version 3.0.12. This is fixed in version 3.0.18. To workaround this issue, avoid blowfish-256.
How severe is CVE-2025-54870?: CVE-2025-54870 has a CVSS 4.0 base score of 8.7, rated high severity.
Is CVE-2025-54870 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-54870?: 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-2025-54870 have an EU (EUVD) identifier?: Yes. CVE-2025-54870 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-23579.
When was CVE-2025-54870 published?: CVE-2025-54870 was published on 2025-08-05 and last updated on 2026-06-17.

References

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