Paper/Archive/CVE-2026-18119

CVE-2026-18119

Concrete CMS Concrete CMS — Concrete CMS below 9.5.3 is vulnerable to Stored XSS via unsanitized inline block custom style values

EPSS 0.5%CVSS 9.0

critical.is priorityof 100

CVSS 9.0 (NVD)9.0 / 10 × 3027.0 Not in CISA KEV+300.0 EPSS percentile 40.1.401 × 208.0 No public exploit+100.0 SSVC exploitation: none+100.0

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource

Concrete CMS5.0.0 – 9.5.2–CNA

Scores by source

NVD9.0CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

ConcreteCMS (CNA)7.0CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N

CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: partial

References

refdocumentation.concretecms.org/developers/introduction/version-history/953-release-notes