{"id":"CVE-2026-8428","aliases":["EUVD-2026-31340","GHSA-prxr-vjgc-2cq9"],"status":"published","title":"CSRF token is not validated in the core CMS update controller for Concrete CMS 9.5.0 and below","description":"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.","severity":{"version":"4.0","score":7.5,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00132,"percentile":0.02823,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-352","CWE-829"],"published":"2026-05-21T20:24:11Z","modified":"2026-10-28T02:31:13Z","fixes":[{"ecosystem":"Packagist","package":"concrete5/concrete5","fixed_in":["9.5.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"concrete5/concrete5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"9.5.1"}]}]},{"source":"osv","ecosystem":"Packagist","package":"concrete5/concrete5","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"9.5.1"}]}],"versions":["8.0","8.0.1","8.0.2","8.0.3","8.1.0","8.2.0","8.2.0RC2","8.2.1","8.3.0","8.3.1","8.3.2","8.4.0","8.4.0RC3","8.4.0RC4","8.4.1","8.4.2","8.4.3","8.4.4","8.4.5","8.5.0","8.5.0RC1","8.5.0RC2","8.5.1","8.5.10","8.5.11","8.5.12","8.5.13","8.5.14","8.5.15","8.5.16","8.5.17","8.5.18","8.5.19","8.5.2","8.5.20","8.5.21","8.5.3","8.5.4","8.5.5","8.5.6","8.5.6RC1","8.5.7","8.5.8","8.5.9","9.0.0","9.0.0RC1","9.0.0RC3","9.0.0RC4","9.0.1","9.0.2","9.1.0","9.1.1","9.1.2","9.1.3","9.2.0","9.2.0RC2","9.2.1","9.2.2","9.2.3","9.2.4","9.2.5","9.2.6","9.2.7","9.2.8","9.2.9","9.3.0","9.3.1","9.3.2","9.3.3","9.3.4","9.3.5","9.3.6","9.3.7","9.3.8","9.3.9","9.4.0","9.4.0RC1","9.4.0RC2","9.4.1","9.4.2","9.4.3","9.4.4","9.4.5","9.4.6","9.4.7","9.4.8","9.5.0","9.5.0RC1","9.5.0RC2"]}],"products":[{"vendor":"concrete cms","product":"concrete cms"},{"vendor":"concretecms","product":"concrete_cms"}],"references":[{"url":"https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes","tags":["release-notes","Release Notes","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-8428","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-prxr-vjgc-2cq9"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8428.json","tags":["advisory"]},{"url":"https://github.com/concretecms/concretecms","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-8428","title":"CSRF token is not validated in the core CMS update controller for Concrete CMS 9.5.0 and below","description":"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 $this-\u003etoken-\u003evalidate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.","status":"published","published":"2026-05-21T20:24:11.572Z","modified":"2026-05-22T13:23:49.586Z","cvss":[{"version":"4.0","score":7.5,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-352","CWE-829"],"updated_at":"2026-11-02T13:48:02.226896Z"}],"euvd":[{"id":"EUVD-2026-31340","description":"Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token-\u003eoutput('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this-\u003etoken-\u003evalidate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.","status":"published","published":"2026-05-21T20:24:11Z","modified":"2026-05-22T13:23:49Z","cvss":[{"version":"4.0","score":7.5,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T18:21:12.491464Z"}],"ghsa":[{"id":"GHSA-prxr-vjgc-2cq9","title":"Concrete CMS is Vulnerable to Cross-Site Request Forgery","description":"Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token-\u003eoutput('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this-\u003etoken-\u003evalidate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES.","status":"published","published":"2026-05-21T21:30:38Z","modified":"2026-06-24T20:57:52Z","cvss":[{"version":"4.0","score":7.5,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-352"],"updated_at":"2026-11-02T14:40:32.744157Z"}],"nvd":[{"id":"CVE-2026-8428","description":"Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token-\u003eoutput('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this-\u003etoken-\u003evalidate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.","status":"published","published":"2026-05-21T21:16:34.387Z","modified":"2026-07-23T16:10:00.137Z","cvss":[{"version":"4.0","score":7.5,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-352","CWE-829"],"updated_at":"2026-11-02T14:12:19.752984Z"}],"osv":[{"id":"CVE-2026-8428","title":"CSRF token is not validated in the core CMS update controller for Concrete CMS 9.5.0 and below","description":"Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token-\u003eoutput('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this-\u003etoken-\u003evalidate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.","status":"published","published":"2026-05-21T20:24:11.572Z","modified":"2026-10-28T02:31:13.933971754Z","cvss":[{"version":"4.0","score":7.5,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-352","CWE-829"],"updated_at":"2026-11-02T15:45:18.482949Z"},{"id":"GHSA-prxr-vjgc-2cq9","title":"Concrete CMS is Vulnerable to Cross-Site Request Forgery","description":"Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($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.","status":"published","published":"2026-05-21T21:30:38Z","modified":"2026-09-10T03:50:47.279597171Z","cvss":[{"version":"4.0","score":7.5,"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","level":"high"}],"cwes":["CWE-352"],"updated_at":"2026-11-02T15:46:53.700556Z"}]}}