CVE-2026-18119 — Concrete CMS below 9.5.3 is vulnerable to Stored XSS via unsanitized inline block custom style values
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…
Published: 2026-09-14 · CVSS: 7.0 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7