{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-8428","assignerOrgId":"ff5b8ace-8b95-4078-9743-eac1ca5451de","state":"PUBLISHED","assignerShortName":"ConcreteCMS","dateReserved":"2026-05-12T18:07:11.189Z","datePublished":"2026-05-21T20:24:11.572Z","dateUpdated":"2026-05-22T13:23:49.586Z"},"containers":{"cna":{"providerMetadata":{"orgId":"ff5b8ace-8b95-4078-9743-eac1ca5451de","shortName":"ConcreteCMS","dateUpdated":"2026-05-21T20:24:11.572Z"},"title":"CSRF token is not validated in the core CMS update controller for Concrete CMS 9.5.0 and below","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-352","description":"CWE-352 Cross-Site request forgery (CSRF)","type":"CWE"}]},{"descriptions":[{"lang":"en","cweId":"CWE-829","description":"CWE-829 Inclusion of functionality from untrusted control sphere","type":"CWE"}]}],"impacts":[{"capecId":"CAPEC-186","descriptions":[{"lang":"en","value":"CAPEC-186 Malicious Software Update"}]}],"affected":[{"vendor":"Concrete CMS","product":"Concrete CMS","collectionURL":"https://github.com/concretecms/concretecms","repo":"https://github.com/concretecms/concretecms","versions":[{"status":"affected","version":"5.0","lessThanOrEqual":"9.5.0","versionType":"git"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"Concrete CMS 9.5.0 and below emits a CSRF token in the local_available_update.php view ($token->output('do_update')) but the corresponding do_update() method in concrete/controllers/single_page/dashboard/system/update/update.php never calls $this->token->validate('do_update'). The form is rendered as a POST form, meaning the token reaches the browser, but because the controller discards it without verification, an attacker can craft a cross-site POST that triggers a core CMS update to an attacker-specified version string.  In order to be vulnerable, theictim must be passing canUpgrade()anda valid update version must be present under DIR_CORE_UPDATES. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.","supportingMedia":[{"type":"text/html","base64":false,"value":"Concrete CMS 9.5.0 and below emits a CSRF token in the <code>local_available_update.php</code> view (<code>$token-&gt;output('do_update')</code>) but the corresponding <code>do_update()</code> method in <code>concrete/controllers/single_page/dashboard/system/update/update.php</code> never calls <code>$this-&gt;token-&gt;validate('do_update')</code>. 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.&nbsp;&nbsp;In order to be vulnerable, theictim must be passing <code>canUpgrade()and</code>a valid update version must be present under <code>DIR_CORE_UPDATES</code>.&nbsp;The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of&nbsp;7.5 with vector&nbsp;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&nbsp;https://github.com/maru1009&nbsp;for reporting.<br>"}]}],"references":[{"url":"https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes","tags":["release-notes"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"ACTIVE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":7.5,"vectorString":"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"}}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.2"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-22T13:23:39.070790Z","id":"CVE-2026-8428","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-05-22T13:23:49.586Z"}}]}}