In short
- CVE-2026-3241 is a MEDIUM (CVSS 4.8) vulnerability affecting concrete5/concrete5, concrete cms (concretecms).
- Chance of exploitation in the next 30 days (EPSS): 0.24%, higher than 14.9% of all vulnerabilities.
- Fix: update to 9.4.8 or later.
Description
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.
NVD description
In Concrete CMS below version 9.4.8, a stored 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 gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks M3dium for reporting.
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