CVE-2021-47961
Synology SSL VPN Client Plaintext Password Storage Vulnerability
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.
INFO
Published Date :
April 10, 2026, 10:16 a.m.
Last Modified :
April 13, 2026, 3:02 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | db201096-a0cc-46c7-9a55-61d9e221bf01 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE |
Solution
- Update Synology SSL VPN Client to version 1.4.5-0684.
- Ensure secure password storage practices are implemented.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-47961.
| URL | Resource |
|---|---|
| https://www.synology.com/en-global/security/advisory/Synology_SA_26_05 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47961 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-47961
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-47961 vulnerability anywhere in the article.
-
CybersecurityNews
Synology SSL VPN Client Vulnerabilities Let Remote Attackers Access Sensitive Files
Synology reveals two severe SSL VPN Client flaws that could let remote attackers steal sensitive files and intercept network traffic. The vulnerabilities affect users running older versions of the sof ... Read more
-
Daily CyberSecurity
VPN Security Alert: Synology Patches Flaws in SSL VPN Client
Synology has released an essential security update for its SSL VPN Client utility, addressing two “Important” severity vulnerabilities that could lead to sensitive data exposure and unauthorized traff ... Read more
The following table lists the changes that have been made to the
CVE-2021-47961 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Apr. 10, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N Added CWE CWE-256 Added Reference https://www.synology.com/en-global/security/advisory/Synology_SA_26_05