Fedify has an incomplete SSRF mitigation after GHSA-p9cg-vqcc-grcx: validatePublicUrl allows special-use IPv4 ranges_CVE-2026-50131

{
    "lastseen": "",
    "description": "Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Fedify previously addressed SSRF/internal network access in GHSA-p9cg-vqcc-grcx by adding public URL validation before runtime document and media fetching. However, the IPv4 validation logic present starting in version 0.11.2 and prior to versions 1.9.12, 1.10.11, 2.0.19, 2.1.15, and 2.2.4 appears incomplete. The `validatePublicUrl()` protection relies on `isValidPublicIPv4Address()` to reject non-public IPv4 destinations. The function blocks common private and local ranges such as `10.0.0.0/8`, `127.0.0.0/8`, `169.254.0.0/16`, `172.16.0.0/12`, and `192.168.0.0/16`, but it still treats several special-use, reserved, multicast, benchmarking, and carrier-grade NAT IPv4 ranges as valid public destinations. Because this validation is used as an SSRF defense before outbound fetches, this appears to be an incomplete mitigation or bypass class for the previous SSRF issue. Versions 1.9.12, 1.10.11, 2.0.19, 2.1.15, and 2.2.4 contain an updated patch.",
    "published": "2026-06-10T20:27:43.370Z",
    "modified": "2026-06-10T20:27:43.370Z",
    "type": "cve",
    "title": "Fedify has an incomplete SSRF mitigation after GHSA-p9cg-vqcc-grcx: validatePublicUrl allows special-use IPv4 ranges",
    "source": "GitHub_M",
    "references": "https://github.com/fedify-dev/fedify/security/advisories/GHSA-xw9q-2mv6-9fr8",
    "id": "CVE-2026-50131",
    "bulletinFamily": "",
    "cwe": [
        "CWE-918",
        "CWE-1286",
        "CWE-1389"
    ],
    "cvelist": null,
    "sourceData": "fedify-dev fedify >= 0.11.2, < 1.9.12\nfedify-dev fedify >= 1.10.0, < 1.10.11\nfedify-dev fedify >= 2.0.0, < 2.0.19\nfedify-dev fedify >= 2.1.0, < 2.1.15\nfedify-dev fedify >= 2.2.0, < 2.2.4\nfedify-dev vocab-runtime < 2.0.19\nfedify-dev vocab-runtime >= 2.1.0, < 2.1.15\nfedify-dev vocab-runtime >= 2.2.0, < 2.2.4",
    "sourceHref": "",
    "cvss": {
        "score": 8.6,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L",
        "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": "fedify",
    "version": ">= 0.11.2, < 1.9.12",
    "vendor": "fedify-dev",
    "ai_description": "Fedify has an incomplete SSRF mitigation, allowing special-use IPv4 ranges as valid public destinations due to incomplete validation logic in the `validatePublicUrl()` function.",
    "ai_severity": "High",
    "ai_vendor": "Fedify-dev",
    "ai_product": "Fedify",
    "ai_version": "0.11.2 to 1.9.11, 1.10.0 to 1.10.10, 2.0.0 to 2.0.18, 2.1.0 to 2.1.14, 2.2.0 to 2.2.3",
    "ai_score": 8.6
}