CVE-2026-3240

Concrete CMS below 9.4.8 is vulnerable to Stored XSS via Legacy form

Published: Mar 4, 2026Updated: Mar 4, 2026 Sources: CVE List NVD GHSACWE-79

4.8MEDIUM

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:HPrivileges Required

High

UI:RUser Interaction

Required

Scope

S:CScope

Changed

Impact

C:LConfidentiality

Low

I:LIntegrity

Low

A:NAvailability

None

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Weaknesses

CWE-79

Affected Products

concretecms

oss-projectaka concrete cms

concrete cms

Web & CMS Plugins

Concrete CMS

commercialaka concrete5

package-ecosystem

Exploitability

1 exploit source identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

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Official Patch Available

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques

Execution

Initial Access

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References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/948-release-notes

documentation.concretecms.org

https://github.com/concretecms/concretecms/pull/12826

github.com

https://nvd.nist.gov/vuln/detail/CVE-2026-3240

nvd.nist.gov

and 1 more references View all →

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