CVE-2021-47960Network attack vector

File disclosure via loopback HTTP server

Published Apr 10, 2026 · Updated Apr 10, 2026

File exposure in Synology SSL VPN Client before 1.4.5-0684 allows remote attackers to read installation-directory files via browser requests. The loopback-bound local HTTP server exposes its installation directory, but Synology has not published the request path or failed access-control operation. Exploitation requires the user to interact with a crafted web page; disclosed consequences are limited to reading configuration files, certificates, and logs.

CVSS severity6.5
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

File exposure in Synology SSL VPN Client before 1.4.5-0684 allows remote attackers to read installation-directory files via browser requests. The loopback-bound local HTTP server exposes its installation directory, but Synology has not published the request path or failed access-control operation. Exploitation requires the user to interact with a crafted web page; disclosed consequences are limited to reading configuration files, certificates, and logs.

The record

CVE
CVE-2021-47960
Published
Apr 10, 2026
Updated
Apr 10, 2026
Vendor
Synology
Product
Synology SSL VPN Client
Classifications
CWE-552, CAPEC-150, CAPEC-639, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <1.4.5-0684

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Synology · Synology SSL VPN Clientversion=* <1.4.5-0684

Published CVSS scores

6.5Synology Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-552Files or Directories Accessible to External Parties
CAPEC-150Collect Data from Common Resource Locations
CAPEC-639Probe System Files
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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