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VULNERABILITIES

CVE-2026-18116 Details

Description

Concrete CMS 8.3.0 to 9.5.2 stored calendar event names without sanitization and rendered them without HTML escaping in the workflow approval and deletion notifications shown in the dashboard "Waiting For Me" block. A registered user permitted to add events to a calendar governed by an approval workflow could submit an event whose name contained a script payload, which then executed in an administrator's browser when the pending request was displayed and could be used to create a new administrator account. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks v01demort for reporting.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:6.1 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes ConcreteCMSBroken Link

Weakness Enumeration

CWE-IDCWE NameSource
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')ConcreteCMS

Affected Products

ProductVersions
concretecms concrete cms
>= 8.3.0, < 9.5.3

CPE

  • cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.

Change History

3 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-18116
NVD Published Date:
Sep 14, 2026
NVD Last Modified:
Sep 21, 2026
Source:
ConcreteCMS
CVE-2026-18116 Details - Not Deferred