CVE-2026-18423 Missing authorization in Concrete CMS

Low 2.1 Published 15 Sep 2026 Updated 15 Sep 2026

Authenticated users can delete or rename saved search presets for entities they lack permission to access, enabling defacement or social engineering.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-18423?

CVE-2026-18423 is a low-severity missing authorization vulnerability in Concretecms Concrete Cms, published on 15 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official description

Concrete CMS 9.0.0 through 9.5.2 is vulnerable to Insecure direct object reference (IDOR) in the Express saved search preset delete and edit dialogs . An authenticated user holding only view permission on a single Express entity could therefore permanently delete, with no undo, or rename saved search presets owned by Express entities for which they had no permission, and a renamed preset name was displayed back to users of the targeted entity, enabling defacement or social engineering. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N. Thanks Yalguun Tumenkhuu ( fg0x0 ) for reporting.

Weakness: CWE-639

Which versions are affected by CVE-2026-18423?

It affects 1 product.

Products include Concretecms Concrete Cms.

How do I fix CVE-2026-18423?

No fix has been published for CVE-2026-18423 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-18423 being exploited?

There is no known exploitation of CVE-2026-18423 in the wild and no public exploit code.

All Concretecms Concrete Cms vulnerabilities

Sources

Also known as GHSA-7vc7-m9pm-w64f.