CVE-2026-18119

critical

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 cr…

Vendor / product: 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.

CVSS

9.0

9.0 (CVSS v3.1)

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Severity source: NVD CVSS v3.1 (nvd@nist.gov)

Timeline (UTC)

Published: 2026-09-14 20:16

Modified: 2026-09-18 19:23

NVD status: Analyzed

Last synced 2 days ago

Verified against the source API 2026-10-27 07:07 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

concretecms / concrete_cms <9.5.3

Weakness classification (CWE)

CWE-79

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

https://documentation.concretecms.org/developers/introduction/version-history/953-release-... ff5b8ace-8b95-4078-9743-eac1ca5451de

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 07:07 UTC · record ↗

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CVE-2026-18119

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Weakness classification (CWE)

Mitigation & advisories

References

Data sources

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