CVE-2026-3240

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.

PUBLISHED Reserved 2026-02-26 | Published 2026-03-04 | Updated 2026-03-04 | Assigner ConcreteCMS

Problem types

CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

Product status

Credits

minhnn42, namdi and quanlna2 from VCSLab-Viettel Cyber Security finder

References

github.com/concretecms/concretecms/pull/12826

documentation.concretecms.org/...n-history/948-release-notes

cve.org (CVE-2026-3240)

nvd.nist.gov (CVE-2026-3240)

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