CVE-2026-18116 (GCVE-0-2026-18116)

Vulnerability from cvelistv5 – Published: 2026-09-14 22:05 – Updated: 2026-09-15 13:39
VLAI
Title
Concrete CMS 8.3.0 to 9.5.2 is vulnerable to Stored XSS in Calendar Event Name via Workflow Approval Notifications
Summary
Concrete CMS 8.3.0 to 9.5.2 stored calendar event names without sanitization and rendered them without HTML escaping in the workflow approval and deletion notifications shown in the dashboard "Waiting For Me" block. A registered user permitted to add events to a calendar governed by an approval workflow could submit an event whose name contained a script payload, which then executed in an administrator's browser when the pending request was displayed and could be used to create a new administrator account. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks v01demort for reporting.
Severity
7.3 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-15 13:39 UTC
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation
Assigner
ConcreteCMS CNA under the mitre root
CNA scorecard B 84/100 over 111 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Concrete CMS Concrete CMS Affected: 8.3.0 , ≤ 9.5.2 (git)
guessed Create a notification for this product.
Credits
v01demort
Show details on NVD website
To clipboard 

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