{"id":"CVE-2026-8428","summary":"CSRF token is not validated in the core CMS update controller for Concrete CMS 9.5.0 and below","details":"Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token-\u003eoutput('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this-\u003etoken-\u003evalidate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.","aliases":["GHSA-prxr-vjgc-2cq9"],"modified":"2026-07-25T03:56:22.479927152Z","published":"2026-05-21T20:24:11.572Z","database_specific":{"cna_assigner":"ConcreteCMS","cwe_ids":["CWE-352","CWE-829"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8428.json"},"references":[{"type":"ADVISORY","url":"https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8428.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-8428"},{"type":"PACKAGE","url":"https://github.com/concretecms/concretecms"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/concretecms/concretecms","events":[{"introduced":"0"},{"fixed":"92bae566b9ec573cfb3017fcbb6db454a6586997"}],"database_specific":{"extracted_events":[{"introduced":"5.0"},{"last_affected":"9.5.0"},{"introduced":"0"},{"fixed":"9.5.1"}],"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*"}}],"versions":["9.5.0","9.5.0RC2","9.5.0RC1","9.4.4","9.4.3","9.4.2","9.4.1","9.4.0","9.4.0RC2","9.4.0RC1","9.3.7","9.3.6","9.3.5","9.3.0","9.3.4","9.3.3","9.3.2","9.3.1","8.4.1","8.3.1","8.2.1","8.2.0","8.2.0RC2","8.1.0","5.7.5.7","5.7.5.6","5.7.5.5","5.7.5.2","5.7.4.1","5.7.3.1","5.7.3","5.7.2.1","5.7.2","5.7.0.4","5.7.1","5.7.0.3","5.7.0.1","5.7.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-8428.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}]}