Concrete CMS up to 9.5.2 Express server-side request forgery

Summaryinfo

A vulnerability marked as problematic has been reported in Concrete CMS up to 9.5.2. This affects an unknown part of the component Express. The manipulation leads to server-side request forgery. This vulnerability is documented as CVE-2026-18423. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Concrete CMS up to 9.5.2 and classified as problematic. This issue affects an unknown code of the component Express. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at documentation.concretecms.org. The identification of this vulnerability is CVE-2026-18423 since 07/30/2026. The exploitation is known to be easy. The attack may be initiated remotely. The exploitation needs additional levels of successful authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/15/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Content Management System

Name

• Concrete CMS

Version

• 9.5.0
• 9.5.1
• 9.5.2

License

• open-source

CPE 2.3info

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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