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Vulnerability record · CVE-2021-47961 · published 10 April 2026

CVE-2021-47961: Synology ssl vpn client vulnerability

Synology · Ssl Vpn Client

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.

8.1 CVSS 3.1 High EPSS 0.32% · top 77.3% CWE-256 · CWE-256
8.1CVSS 3.1 base score
0.32%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.synology.com/en-global/security/advisory/Synology_SA_26_05 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.1CVE-2018-8929Synology ssl vpn client cleartext transmission vulnerabilityImproper restriction of communication channel to intended endpoints vulnerability in HTTP daemon in Synology SSL VPN Client before 1.2.4-0224 allows …EPSS 0.75%7.4CVE-2018-13283Synology ssl vpn client vulnerabilityLack of administrator control over security vulnerability in client.cgi in Synology SSL VPN Client before 1.2.5-0226 allows remote attackers to condu…EPSS 1.4%6.5CVE-2021-47960Synology ssl vpn client vulnerabilityA files or directories accessible to external parties vulnerability in Synology SSL VPN Client before 1.4.5-0684 allows remote attackers to access fi…EPSS 0.19%5.5CVE-2023-5748Synology ssl vpn client classic buffer overflow vulnerabilityBuffer copy without checking size of input ('Classic Buffer Overflow') vulnerability in cgi component in Synology SSL VPN Client before 1.4.7-0687 al…EPSS 0.19%

Source: NIST National Vulnerability Database (record CVE-2021-47961), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.