TinaCMS: Cross-origin postMessage handlers and rich-text URL-sanitization bypass enable stored XSS and session takeover_CVE-2026-55660

{
    "lastseen": "",
    "description": "Tina is a headless content management system. In versions prior to @tinacms/app 2.5.6 and tinacms 3.9.3, cross-origin postMessage handlers and a rich-text URL-sanitization bypass enable stored XSS and session takeover. The library registers window message listeners \u2014 the useTina overlay handler, the OAuth authentication popup handler, and the admin\u2194preview iframe GraphQL reducer \u2014 that act on event.data without verifying event.origin or event.source and post messages using non-specific target origins, while insufficient URL sanitization in rich-text content allows malicious URLs to persist and execute. A page the victim visits (or a window in an opener/iframe relationship with a Tina admin) can forge messages to drive the editor, inject preview content, or observe/forge the OAuth popup channel to take over an authenticated editing session. This issue has been fixed in versions @tinacms/app 2.5.6 and tinacms 3.9.3.",
    "published": "2026-07-01T21:00:27.321Z",
    "modified": "2026-07-01T21:00:27.321Z",
    "type": "cve",
    "title": "TinaCMS: Cross-origin postMessage handlers and rich-text URL-sanitization bypass enable stored XSS and session takeover",
    "source": "GitHub_M",
    "references": "https://github.com/tinacms/tinacms/security/advisories/GHSA-g5qx-h5f3-mp2f\nhttps://github.com/tinacms/tinacms/pull/7056",
    "id": "CVE-2026-55660",
    "bulletinFamily": "",
    "cwe": [
        "CWE-79",
        "CWE-346",
        "CWE-601",
        "CWE-940"
    ],
    "cvelist": null,
    "sourceData": "tinacms tinacms < 3.9.3\ntinacms @tinacms/app < 2.5.6",
    "sourceHref": "",
    "cvss": {
        "score": 7.6,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "tinacms",
    "version": "< 3.9.3",
    "vendor": "tinacms",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}