CVE-2021-47958Public exploitNetwork attack vector

Authenticated internal-service access via SVG image references

Published May 15, 2026 · Updated May 15, 2026

Server-side request forgery in CouchCMS 2.2.1 allows remote authenticated users to reach internal services through SVG uploads. The browse.php file manager accepts an uploaded SVG whose image xlink:href points to an attacker-chosen URL, causing server-side retrieval without restricting the destination. A valid CouchCMS session and upload nonce are required; successful requests originate from the CMS host and can interact with services unavailable to the user directly.

CVSS severity5.3
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side request forgery in CouchCMS 2.2.1 allows remote authenticated users to reach internal services through SVG uploads. The browse.php file manager accepts an uploaded SVG whose image xlink:href points to an attacker-chosen URL, causing server-side retrieval without restricting the destination. A valid CouchCMS session and upload nonce are required; successful requests originate from the CMS host and can interact with services unavailable to the user directly.

The record

CVE
CVE-2021-47958
Published
May 15, 2026
Updated
May 15, 2026
Vendor
CouchCMS
Product
CouchCMS
Classifications
CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 15, 2026CVE publishedPublication date reported by the CVE source.
  2. May 15, 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=2.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

CouchCMS · CouchCMSversion=2.2.1

Published CVSS scores

5.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L
4.3VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

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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