CVE-2026-3241

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.

PUBLISHED Reserved 2026-02-26 | Published 2026-03-04 | Updated 2026-03-04 | Assigner ConcreteCMS

Problem types

CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

Product status

Credits

M3dium reporter

References

github.com/concretecms/concretecms/pull/12826

documentation.concretecms.org/...n-history/948-release-notes

cve.org (CVE-2026-3241)

nvd.nist.gov (CVE-2026-3241)

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