CVE-2026-85385

Concrete CMS below 9.5.4 did not validate the user timezone value (uTimezone) on write and rendered it without output encoding on the Dashboard user management page, where Date::getTimezoneDisplayName() returns any non-IANA value unchanged. A stored cross-site scripting payload saved in this field executed in an administrator's browser when they viewed the affected user in the Dashboard, running script in the admin session (for example to read CSRF tokens, create administrator accounts, or change site settings). In Concrete CMS 9.5.3 the field became reachable by unauthenticated visitors through public registration; in Concrete CMS below 9.5.3, the same field was reachable by any authenticated user through the account profile editor. Exploitation required concrete.misc.user_timezones to be enabled (off by default), and the unauthenticated path additionally required public registration to be enabled. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.7 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Suraj Bhosale for reporting.
Configurations

Configuration 1 (hide)

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

History

21 Sep 2026, 17:52

Type Values Removed Values Added
CPE cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*
References () https://documentation.concretecms.org/developers/introduction/version-history/954-release-notes - () https://documentation.concretecms.org/developers/introduction/version-history/954-release-notes - Broken Link
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 9.6
First Time Concretecms
Concretecms concrete Cms

16 Sep 2026, 17:18

Type Values Removed Values Added
New CVE

Information

Published : 2026-09-16 17:18

Updated : 2026-09-21 17:52


NVD link : CVE-2026-85385

Mitre link : CVE-2026-85385

CVE.ORG link : CVE-2026-85385


JSON object : View

Products Affected

concretecms

  • concrete_cms
CWE
CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')