{"id":"CVE-2026-3240","aliases":["GHSA-45fj-fvmm-xcc5"],"url":"https://o3.security/vulnerability/CVE-2026-3240","summary":"Concrete CMS below 9.4.8 is vulnerable to Stored XSS via Legacy form","details":"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":"2026-03-04T02:15:53.400Z","modified":"2026-08-12T03:51:21.180207245Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"concrete5/concrete5","fixedVersion":"9.4.8"}],"fix":{"url":"https://github.com/concretecms/concretecms/pull/12826","label":"concretecms/concretecms#12826"},"references":[{"type":"WEB","url":"https://documentation.concretecms.org/9-x/developers/introduction/version-history/948-release-notes"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3240.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3240"},{"type":"FIX","url":"https://github.com/concretecms/concretecms/pull/12826"},{"type":"PACKAGE","url":"https://github.com/concretecms/concretecms"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:21.180207245Z"}}