CVE-2021-34808Network attack vector

Unauthenticated access to intranet resources

Published Jun 18, 2021 · Updated Sep 17, 2024

SSRF in the CGI component of Synology Media Server before 1.8.3-2881 allows remote attackers to access intranet resources. Synology identifies the CGI component but has not disclosed the affected endpoint, parameter, or request-handling error. No authentication or user interaction is required; the consequence is limited to indirect access to resources reachable from the NAS.

CVSS severity5.8
Medium
EPSS probability1.02%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in the CGI component of Synology Media Server before 1.8.3-2881 allows remote attackers to access intranet resources. Synology identifies the CGI component but has not disclosed the affected endpoint, parameter, or request-handling error. No authentication or user interaction is required; the consequence is limited to indirect access to resources reachable from the NAS.

The record

CVE
CVE-2021-34808
Published
Jun 18, 2021
Updated
Sep 17, 2024
Vendor
Synology
Product
Media Server
Classifications
CWE-918, CAPEC-664
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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=unspecified <1.8.3-2881

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Synology · Media Serverversion=unspecified <1.8.3-2881

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
5.8Synology Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/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-918Server-Side Request Forgery (SSRF)
CAPEC-664Server Side Request Forgery

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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