CVE-2026-81897 — Concrete CMS below version 9.5.3 is vulnerable to Stored XSS via Express form Text control save_control
In Concrete CMS below CMS 9.5.3, the save_control action in the Express entities forms dashboard controller did not validate the anti-CSRF token. By causing an authenticated adm…
Published: 2026-09-15 · CVSS: 7.7 · CVSS 4.0
In Concrete CMS below CMS 9.5.3, the save_control action in the Express entities forms dashboard controller did not validate the anti-CSRF token. By causing an authenticated administrator to submit a forged cross-site request, a remote attacker without credentials could write attacker-controlled headline and body values to an existing Express form Text control. Those values were emitted without output encoding by the Express form Text element, so the injected markup executed as persistent JavaScript for any administrator who later opened the affected entry, resulting in stored cross-site scripting. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.7 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7