What is CVE-2025-25567?

CVE-2025-25567 is a critical-severity vulnerability in Softether Vpn, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2025-03-12.

How severe is CVE-2025-25567?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Softether Vpn

CVE-2025-25567

SoftEther VPN 5.02.5187 is vulnerable to Buffer Overflow in Internat.c via the UniToStrForSingleChars function. NOTE: the Supplier disputes this because the behavior only enables a local user to attack himself through the UI,

Vulnerability class: Buffer Overflow

Published 2025-03-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (45.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 45.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000

Affected products

Softether Vpn — versions 5.02.5187

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

Frequently asked questions

What is CVE-2025-25567?: CVE-2025-25567 is a critical-severity vulnerability in Softether Vpn, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2025-03-12.
How severe is CVE-2025-25567?: Critical severity. CVSS v3 base score is 9.8 out of 10.