CVE-2026-3240

Name: CVE-2026-3240
Creator: NVD / NIST
Published: 2026-03-04T03:16:04.94+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.8/10EPSS 0.21%

Last modified Jun 17, 2026

CVE-2026-3240 is a medium-severity vulnerability rated 4.8/10 on the CVSS scale. 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.. EPSS estimates a 0.21% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

4.8/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

CVSS 4.0

4.8/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.21%

11.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Concretecms	Concrete Cms	< 9.4.8

References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/948-release-notesPatch, Release Notes, Vendor Advisory
https://github.com/concretecms/concretecms/pull/12826Exploit, Issue Tracking, Vendor Advisory

Timeline

Published: Mar 4, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-3240?

How severe is CVE-2026-3240?

CVE-2026-3240 has a CVSS score of 4.8/10 (MEDIUM severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-3240?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-3240?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST