CVE-2026-3240 MEDIUM

CVE-2026-3240: Concrete CMS below 9.4.8 is vulnerable to Stored XSS via Legacy form

Vendor Concrete Cms
Product Concrete CMS
Weakness CWE-79 · XSS
Published March 4, 2026
Last update March 4, 2026
View on NVD All CVEs

CVSS base score

4.8/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction —
Confidentiality —
Integrity —

CVSS 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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 4, 2026 CVE published
March 4, 2026 Record updated