medium4.8
CVE-2026-3241
Concrete CMS has a stored Cross-site Scripting (XSS) vulnerability
Impact
In Concrete CMS below version 9.4.8, a Cross-site Scripting (XSS) vulnerability exists in the "Legacy Form" block. An authenticated user with permissions to create or edit forms (e.g., a rogue administrator) can inject a persistent JavaScript payload into the options of a multiple-choice question (Checkbox List, Radio Buttons, or Select Box). This payload is then executed in the browser of any user who views the page containing the form. The Concrete CMS security team thanks M3dium for reporting.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | concrete5/concrete5 | < 9.4.8 | 9.4.8 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Concretecms | Concrete Cms | before 9.4.8 |