Concrete CMS 9.5.0 and below is vulnerable to IDOR in ‘/ccm/frontend/conversations/message_page’ allowing unauthenticated read of any conversation message_CVE-2026-8238

{
    "lastseen": "",
    "description": "Concrete CMS 9.5.0 and below is vulnerable to IDOR.\u00a0The\u00a0'/ccm/frontend/conversations/message_page'\u00a0endpoint returns the full content of any conversation message. An unauthenticated attacker can enumerate all conversation messages, including messages from restricted pages, member-only areas, and the moderation queue. File attachments with download URLs are also exposed.\u00a0The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of\u00a06.3 with Vector\u00a0CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Tristan Madani for reporting.",
    "published": "2026-05-21T21:04:50.691Z",
    "modified": "2026-05-21T21:04:50.691Z",
    "type": "cve",
    "title": "Concrete CMS 9.5.0 and below is vulnerable to IDOR in '/ccm/frontend/conversations/message_page' allowing unauthenticated read of any conversation message",
    "source": "ConcreteCMS",
    "references": "https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes",
    "id": "CVE-2026-8238",
    "bulletinFamily": "",
    "cwe": [
        "CWE-862"
    ],
    "cvelist": null,
    "sourceData": "Concrete CMS Concrete CMS 5.0",
    "sourceHref": "",
    "cvss": {
        "score": 6.3,
        "severity": "MEDIUM",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
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        "baseScore": 0,
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        "confidentialityImpact": "",
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        "availabilityImpact": "",
        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Concrete CMS",
    "version": "5.0",
    "vendor": "Concrete CMS",
    "ai_description": "",
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    "ai_score": 0
}