CVE-2026-8204 — Concrete CMS 9.5.0 and below is vulnerable to Authorization Bypass in the Calendar Event Frontend Dialog
Concrete CMS 9.5.0 and below is vulnerable to authorization Bypass in the Calendar Event Frontend Dialog which can allow cross-calendar data disclosure. A public calendar block …
Published: 2026-05-21 · CVSS: 6.3 · CVSS 4.0
Concrete CMS 9.5.0 and below is vulnerable to authorization Bypass in the Calendar Event Frontend Dialog which can allow cross-calendar data disclosure. A public calendar block can be used as a pivot point to access private calendar data. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7