CVE-2026-68526

Medium

Description

Concrete CMS before 9.5.3 did not validate an anti-CSRF token in the Calendar event duplicate dialog controller (concrete/controllers/dialog/event/duplicate.php) submit() action, which duplicated a calendar event after checking only canAccess() and the per-resource canAddCalendarEvent() permission, so a crafted cross-site request could cause an authenticated user with add-event permission to create duplicate CalendarEvents and CalendarEventVersions records under their own authority. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.3 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

SeverityMedium
CVSS4.3
Exploit probability—
ProductConcretecms Concrete Cms
PublishedSep 11, 2026
First seenSep 11, 2026

How to fix

Update
  • concretecms concrete_cms9.5.3 or later

Affected products

ProductAffected versionsFixed in
concretecms concrete_cmsv < 9.5.39.5.3

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