CVE-2026-3240
Medium
Description
In Concrete CMS below version 9.4.8, a user with permission to edit a page with element Legacy form can perform a stored XSS attack towards high-privilege accounts via the Question field. 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 minhnn42, namdi and quanlna2 from VCSLab-Viettel Cyber Security for reporting.
SeverityMedium
CVSS4.8
Exploit probability—
Product
Concretecms Concrete Cms
PublishedMar 4, 2026
First seenMar 4, 2026
Weakness typeCWE-79Cross-site scripting (XSS)
How to fix
Update
- concretecms concrete_cms9.4.8 or later
- concrete5/concrete59.4.8 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| concretecms concrete_cms | v < 9.4.8 | 9.4.8 |
| concrete5/concrete5Packagist | v < 9.4.8 | 9.4.8 |
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