Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration_CVE-2026-56104

{
    "lastseen": "",
    "description": "Chainlit before 2.10.1 contains a session hijacking vulnerability that allows unauthenticated attackers to restore and inherit authenticated user sessions by presenting a valid sessionId during WebSocket session restoration without ownership verification. Attackers can exploit the restore_existing_session path to assume a victim's permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.",
    "published": "2026-06-22T14:17:52.640Z",
    "modified": "2026-06-22T14:17:52.640Z",
    "type": "cve",
    "title": "Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration",
    "source": "VulnCheck",
    "references": "https://github.com/Chainlit/chainlit/releases/tag/2.10.1\nhttps://github.com/Chainlit/chainlit/pull/2857\nhttps://github.com/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f\nhttps://www.vulncheck.com/advisories/chainlit-session-hijacking-via-websocket-session-restoration",
    "id": "CVE-2026-56104",
    "bulletinFamily": "",
    "cwe": [
        "CWE-862"
    ],
    "cvelist": null,
    "sourceData": "Chainlit chainlit 0",
    "sourceHref": "",
    "cvss": {
        "score": 9.1,
        "severity": "CRITICAL",
        "vector": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/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": "chainlit",
    "version": "0",
    "vendor": "Chainlit",
    "ai_description": "Session hijacking vulnerability via WebSocket session restoration",
    "ai_severity": "Critical",
    "ai_vendor": "Chainlit",
    "ai_product": "Chainlit",
    "ai_version": "< 2.10.1",
    "ai_score": 9.1
}