Vulnerability · Published May 21, 2026 · Assigned by ConcreteCMS

CVE-2026-7890Concrete CMS 9.5.0 is vulnerable to SSRF via RSS Displayer Block

Low 2.1

In plain English

A low-severity server-side request forgery in Concrete CMS from Concrete CMS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)2.1Low

Exploit odds (30 days)0.2%top 95.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	concrete5/concrete5	9.5.1	GHSA-gjwq-9v8p-47w7

Affected products (as reported)

Vendor	Product	Versions
Concrete CMS	Concrete CMS	5.0 – through 9.5.0

Weakness: CWE-918 · 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

References

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