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CVE-2026-81918

4.8 · MEDIUM

Concrete CMS below 9.5.3 is vulnerable to Stored XSS via the Date Format field in the Page Attribute Display block.

Published Sep 11, 2026concretecmsCWE-79EPSS 0.25%

Overview

CVE-2026-81918 is a medium-severity vulnerability affecting concretecms concrete_cms. It was published on September 11, 2026 and has a CVSS 3.1 base score of 4.8 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 4.8, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

Concrete CMS below 9.5.3 is vulnerable to Stored XSS via the Date Format field in the Page Attribute Display block. A user with edit_page_contents permissions could store a payload which executes in the browser of any visitor who viewed a page where the block was configured to display a date-type attribute. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Oriol Ortiz for reporting.

Remediation

Check the references section for vendor advisories and patches from concretecms. Update concrete_cms to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected products

VendorProductVersionsStatus
concretecmsconcrete_cms>= 0, < 9.5.3Affected

Frequently asked questions

What is CVE-2026-81918?

CVE-2026-81918 is a medium-severity vulnerability affecting concretecms concrete_cms. It was published on September 11, 2026 and has a CVSS 3.1 base score of 4.8 (MEDIUM).

How severe is CVE-2026-81918?

This vulnerability has a CVSS 3.1 base score of 4.8, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-81918?

Check the references section for vendor advisories and patches from concretecms. Update concrete_cms to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-81918?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-81918 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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