CVE-2026-3241
Published:March 04, 2026
Updated:June 27, 2026
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.
Affected Packages
https://github.com/concretecms/concretecms.git (GITHUB):
Affected version(s) >=9.4.0RC1 <9.4.8Fix Suggestion:
Update to version 9.4.8https://github.com/concretecms/concretecms.git (GITHUB):
Affected version(s) =9.5.0RC1 <9.5.0RC2Fix Suggestion:
Update to version 9.5.0RC2concrete5/concrete5 (PHP):
Affected version(s) >=dev-allow-install-php-8.2 <9.4.8Fix Suggestion:
Update to version 9.4.8Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
4.8
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
HIGH
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
2.4
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
EPSS
Base Score:
0.21