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

What is CVE-2026-7890?

CVE-2026-7890 is a low-severity server-side request forgery vulnerability in Concretecms Concrete Cms, published on 21 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.

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.

Weakness: CWE-918

Which versions are affected by CVE-2026-7890?

2 open source packages ship an affected version, including concrete5/concrete5. It affects 1 product.

Products include Concretecms Concrete Cms.

How do I fix CVE-2026-7890?

Upgrade concrete5/concrete5 to 9.5.1 or later.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-7890 being exploited?

There is no known exploitation of CVE-2026-7890 in the wild and no public exploit code.

Other vulnerabilities in Concretecms Concrete Cms

• CVE-2023-48648 Concrete CMS allows unauthorized access because directories can be created with insecure permissions Critical 9.8
• CVE-2022-21829 Code injection in concrete CMS Critical 9.8
• CVE-2021-22958 Server-Side Request Forgery vulnerability in concrete5 Critical 9.8
• CVE-2021-40098 Path traversal in n/a Critical 9.8
• CVE-2026-8134 Concrete CMS Vulnerable to Relative Path Traversal Critical 9.4

All Concretecms Concrete Cms vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-gjwq-9v8p-47w7.