CVE-2026-7890 PUBLISHED

Concrete CMS 9.5.0 is vulnerable to SSRF via RSS Displayer Block

Assigner: ConcreteCMS
Reserved: 05.05.2026 Published: 21.05.2026 Updated: 22.05.2026

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.

Metrics

CVSS 4.0

CVSS 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
CVSS Score: 2.1

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	Low
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	High
User Interaction	None

CVSS 4.0

Product Status

Vendor	Concrete CMS
Product	Concrete CMS
Versions	Default: unaffected affected from 5.0 to 9.5.0 (incl.)

References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes

Problem Types

CWE-918 Server-Side request forgery (SSRF) CWE

Impacts

CAPEC-664 Server Side Request Forgery