Cal.com has an Authentication Bypass via Unvalidated Email in Custom JWT Callback_CVE-2026-23478

{
    "lastseen": "",
    "description": "Cal.com is open-source scheduling software. From 3.1.6 to before 6.0.7, there is a vulnerability in a custom NextAuth JWT callback that allows attackers to gain full authenticated access to any user's account by supplying a target email address via session.update(). This vulnerability is fixed in 6.0.7.",
    "published": "2026-01-13T21:37:35.541Z",
    "modified": "2026-01-13T21:37:35.541Z",
    "type": "cve",
    "title": "Cal.com has an Authentication Bypass via Unvalidated Email in Custom JWT Callback",
    "source": "GitHub_M",
    "references": "https://github.com/calcom/cal.com/security/advisories/GHSA-7hg4-x4pr-3hrg",
    "id": "CVE-2026-23478",
    "bulletinFamily": "",
    "cwe": [
        "CWE-602",
        "CWE-639"
    ],
    "cvelist": null,
    "sourceData": "calcom cal.com >= 3.1.6, < 6.0.7",
    "sourceHref": "",
    "cvss": {
        "score": 10,
        "severity": "CRITICAL",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:L",
        "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": "cal.com",
    "version": ">= 3.1.6, < 6.0.7",
    "vendor": "calcom",
    "ai_description": "Authentication bypass vulnerability via unvalidated email in custom JWT callback",
    "ai_severity": "Critical",
    "ai_vendor": "Cal.com",
    "ai_product": "cal.com",
    "ai_version": "3.1.6 to 6.0.7",
    "ai_score": 10
}