Concrete CMS below 9.5.3 did not sanitize custom style values in the Block Design dialog before writing them into page CSS via a DOM sink, permitting stored cross-site scripting. An editor-level user could execute script in an administrator's session and escalate privileges. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.0 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Nguyen Manh Thuan for reporting.
Advisories

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Fixes

Solution

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Workaround

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History

Mon, 14 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 14 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
Description Concrete CMS below 9.5.3 did not sanitize custom style values in the Block Design dialog before writing them into page CSS via a DOM sink, permitting stored cross-site scripting. An editor-level user could execute script in an administrator's session and escalate privileges. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.0 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Nguyen Manh Thuan for reporting.
Title Concrete CMS below 9.5.3 is vulnerable to Stored XSS via unsanitized inline block custom style values
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: ConcreteCMS

Published:

Updated: 2026-09-14T20:07:08.323Z

Reserved: 2026-07-28T18:02:02.837Z

Link: CVE-2026-18119

cve-icon Vulnrichment

Updated: 2026-09-14T20:07:00.322Z

cve-icon NVD

Status : Received

Published: 2026-09-14T20:16:42.563

Modified: 2026-09-14T20:16:42.563

Link: CVE-2026-18119

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses