Vulnerability in Synology SSL Vpn Client

CVE-2021-47961

A plaintext storage of a password vulnerability in Synology SSL VPN Client before 1.4.5-0684 allows remote attackers to access or influence the user's PIN code due to insecure storage. This may lead to unauthorized VPN configuration and potential interception of subsequent VPN traffic when combined with user interaction.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (22.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 22.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-47961: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-47961?
CVE-2021-47961 is a high-severity vulnerability in Synology SSL Vpn Client, classified under Plaintext Storage of a Password. CVSS score: 8.1/10. Published 2026-04-10.
How severe is CVE-2021-47961?
High severity. CVSS v3 base score is 8.1 out of 10.