CVE-2026-8203

Concrete CMS 9.5.0 and below has Stored XSS on the height parameter. The controller does not validate or sanitize $height. Any user with editor privileges can inject malicious JavaScript that executes in the context of any visitor's browser, potentially leading to session hijacking, credential theft, or other malicious actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Alfin Joseph for reporting.

CVSS v3 5.4 MEDIUM

5.4^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.3 / Impact : 2.7

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction REQUIRED

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes	Release Notes

Configurations

Configuration 1 (hide)

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

History

26 May 2026, 18:33

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 5.4
First Time		Concretecms concrete Cms Concretecms
References	~~() https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes -~~	() https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes - Release Notes
CPE		cpe:2.3:a:concretecms:concrete_cms::::::::

21 May 2026, 21:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-21 21:16

Updated : 2026-05-26 18:33

NVD link : CVE-2026-8203

Mitre link : CVE-2026-8203

CVE.ORG link : CVE-2026-8203

JSON object : View

Products Affected

concretecms

concrete_cms

CWE

CWE-79

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

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