{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-81925","assignerOrgId":"ff5b8ace-8b95-4078-9743-eac1ca5451de","state":"PUBLISHED","assignerShortName":"ConcreteCMS","dateReserved":"2026-08-27T18:25:17.660Z","datePublished":"2026-09-15T20:07:01.834Z","dateUpdated":"2026-09-16T17:48:00.821Z"},"containers":{"cna":{"providerMetadata":{"orgId":"ff5b8ace-8b95-4078-9743-eac1ca5451de","shortName":"ConcreteCMS","dateUpdated":"2026-09-15T20:07:01.834Z"},"title":"Concrete CMS below 9.5.3 is vulnerable to Reflected Cross-Site Scripting (XSS) via Conversation Custom Date Format","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-79","description":"CWE-79 Improper Neutralization of Input During Web Page Generation","type":"CWE"}]}],"impacts":[{"capecId":"CAPEC-591","descriptions":[{"lang":"en","value":"CAPEC-591 Reflected XSS"}]}],"affected":[{"vendor":"Concrete CMS","product":"Concrete CMS","collectionURL":"https://github.com/concretecms/concretecms","repo":"https://github.com/concretecms/concretecms","versions":[{"status":"affected","version":"5.0.0","lessThanOrEqual":"9.5.2","versionType":"git"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"Concrete CMS before 9.5.3 improperly neutralized a user-supplied custom date format when rendering conversation messages, resulting in reflected cross-site scripting. An attacker could execute arbitrary JavaScript in the browser of a user who was tricked into submitting a crafted POST request to the conversation view endpoint. Exploitation was aided by the absence of a CSRF token on the endpoint, which allowed the payload to be delivered through an auto-submitting cross-origin POST without authentication. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p><span>Concrete CMS before 9.5.3 improperly neutralized a user-supplied custom date format when rendering conversation messages, resulting in reflected cross-site scripting. An attacker could execute arbitrary JavaScript in the browser of a user who was tricked into submitting a crafted POST request to the conversation view endpoint. Exploitation was aided by the absence of a CSRF token on the endpoint, which allowed the payload to be delivered through an auto-submitting cross-origin POST without authentication.</span>&nbsp;The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.</p>"}]}],"references":[{"url":"https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes","tags":["release-notes"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"PASSIVE","vulnConfidentialityImpact":"LOW","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","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":"LOW","baseScore":2.1,"vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"}}],"credits":[{"lang":"en","value":"tenzai","type":"finder"}],"source":{"defect":["HackerOne"],"advisory":"3802509","discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-16T17:46:17.138727Z","id":"CVE-2026-81925","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-16T17:48:00.821Z"}}]}}