CVE-2026-7890
Received Received - Intake
RSS Displayer Block Server-Side Request Forgery in Concrete CMS

Publication date: 2026-05-21

Last updated on: 2026-05-22

Assigner: ConcreteCMS

Description
In Concrete CMS 9.5.0 and below, the RSS Displayer block accepts a feed URL from any page editor and fetches it server-side without validation enabling redirect-to-internal bypasses.  The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.1 with a vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:L/SI:N/SA:N.
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Meta Information
Published
2026-05-21
Last Modified
2026-05-22
Generated
2026-06-11
AI Q&A
2026-05-22
EPSS Evaluated
2026-06-10
NVD
CVE-2026-7890
EUVD
EUVD-2026-31379
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
concretecms concrete_cms to 9.5.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
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Executive Summary

This vulnerability exists in Concrete CMS version 9.5.0 and below, specifically in the RSS Displayer block. The block accepts a feed URL from any page editor and fetches it server-side without validating the URL properly. This lack of validation allows attackers to perform redirect-to-internal bypasses.

Impact Analysis

The vulnerability could allow an attacker with high privileges (page editor) to cause the server to fetch unintended internal resources by bypassing URL validation. This could potentially lead to information disclosure or other unintended server-side actions, although the overall severity is low as indicated by the CVSS score of 2.1.

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