FastGPT: DNS rebinding TOCTOU bypass in isInternalAddress allows SSRF on all protected endpoints_CVE-2026-42344

{
    "lastseen": "",
    "description": "FastGPT is an AI Agent building platform. In versions 4.14.11 and prior, FastGPT's isInternalAddress() function in packages/service/common/system/utils.ts is vulnerable to DNS rebinding (TOCTOU \u2014 Time-of-Check to Time-of-Use). The function resolves the hostname via dns.resolve4()/dns.resolve6() and checks resolved IPs against private ranges, but the actual HTTP request happens in a separate call with a new DNS resolution, allowing the DNS record to change between validation and fetch. At time of publication, there are no publicly available patches.",
    "published": "2026-05-08T22:10:00.875Z",
    "modified": "2026-05-08T22:10:00.875Z",
    "type": "cve",
    "title": "FastGPT: DNS rebinding TOCTOU bypass in isInternalAddress allows SSRF on all protected endpoints",
    "source": "GitHub_M",
    "references": "https://github.com/labring/FastGPT/security/advisories/GHSA-cc8x-jrqv-hmwh",
    "id": "CVE-2026-42344",
    "bulletinFamily": "",
    "cwe": [
        "CWE-367"
    ],
    "cvelist": null,
    "sourceData": "labring FastGPT <= 4.14.11",
    "sourceHref": "",
    "cvss": {
        "score": 6.3,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N",
        "version": "3.1"
    },
    "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": "FastGPT",
    "version": "<= 4.14.11",
    "vendor": "labring",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}