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Vulnerability record · CVE-2026-18119 · published 14 September 2026

CVE-2026-18119: Concretecms concrete cms cross-site scripting vulnerability

Concretecms · Concrete Cms

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.

7.0 CVSS 4.0 High EPSS 0.31% · top 78.4% CWE-79 · Cross-site scripting
7.0CVSS 4.0 base score
0.31%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
18 Sep 2026Last modified by NVD

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.

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes Broken Link

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-18119), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.