Rocket.Chat: Email Parameter Fallback Leads To Account Takeover Within Apple OAuth_CVE-2026-55666

{
    "lastseen": "",
    "description": "Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13, in apps/meteor/app/apple/server/loginHandler.ts, handleIdentityToken parses a JWT issued by Apple during the OAuth flow. The try block checks for an email parameter. If the JWT does not contain an email address, the application falls back to accepting an arbitrary email value supplied directly in the request. Attackers are able to forge Apple JWTs that do not contain an email address and leverage this vulnerability to carry out account takeover attacks. This vulnerability is fixed in 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13.",
    "published": "2026-06-24T21:06:55.637Z",
    "modified": "2026-06-24T21:06:55.637Z",
    "type": "cve",
    "title": "Rocket.Chat: Email Parameter Fallback Leads To Account Takeover Within Apple OAuth",
    "source": "GitHub_M",
    "references": "https://github.com/RocketChat/Rocket.Chat/security/advisories/GHSA-wx3c-76rf-wpwf",
    "id": "CVE-2026-55666",
    "bulletinFamily": "",
    "cwe": [
        "CWE-287",
        "CWE-288"
    ],
    "cvelist": null,
    "sourceData": "RocketChat Rocket.Chat >= 8.5.0-rc.0, < 8.5.1\nRocketChat Rocket.Chat >= 8.4.0-rc.0, < 8.4.4\nRocketChat Rocket.Chat >= 8.3.0-rc.0, < 8.3.6\nRocketChat Rocket.Chat >= 8.2.0-rc.0, < 8.2.6\nRocketChat Rocket.Chat >= 8.1.0-rc.0, < 8.1.6\nRocketChat Rocket.Chat >= 7.11.0-rc.0, < 8.0.7\nRocketChat Rocket.Chat < 7.10.13",
    "sourceHref": "",
    "cvss": {
        "score": 9.3,
        "severity": "CRITICAL",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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": "Rocket.Chat",
    "version": ">= 8.5.0-rc.0, < 8.5.1",
    "vendor": "RocketChat",
    "ai_description": "Account takeover vulnerability in Rocket.Chat due to email parameter fallback in Apple OAuth flow",
    "ai_severity": "Critical",
    "ai_vendor": "RocketChat",
    "ai_product": "Rocket.Chat",
    "ai_version": "8.5.0-rc.0 to 8.5.1, 8.4.0-rc.0 to 8.4.4, 8.3.0-rc.0 to 8.3.6, 8.2.0-rc.0 to 8.2.6, 8.1.0-rc.0 to 8.1.6, 7.11.0-rc.0 to 8.0.7, less than 7.10.13",
    "ai_score": 9.3
}