An issue was discovered in QPDF before 7.0.0. There is an infinite loop due to looping xref tables in QPDF.cc.
[
    {
        "id": "CVE-2017-18186-bb259821",
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Function",
        "digest": {
            "function_hash": "143470664312351326887922365433873313335",
            "length": 1526.0
        },
        "target": {
            "file": "libqpdf/QPDF.cc",
            "function": "QPDF::read_xref"
        },
        "source": "https://github.com/qpdf/qpdf/commit/85f05cc57ffa0a863d9d9b23e73acea9410b2937"
    },
    {
        "id": "CVE-2017-18186-be9f9cba",
        "deprecated": false,
        "signature_version": "v1",
        "signature_type": "Line",
        "digest": {
            "line_hashes": [
                "266438603850559179889971379008137572864",
                "170858492933963275451002373626649560772",
                "86906268882115607882227833084113952493",
                "29964010784280242289628928258739117002",
                "78468669523777775192181095830342106787",
                "148108207355360572343990471531997700227",
                "76475920812149409294602624238930904875",
                "168508622536348576714227445013227533227",
                "79954515655412324376867276884929413567",
                "336149513343406209498739849406371991950"
            ],
            "threshold": 0.9
        },
        "target": {
            "file": "libqpdf/QPDF.cc"
        },
        "source": "https://github.com/qpdf/qpdf/commit/85f05cc57ffa0a863d9d9b23e73acea9410b2937"
    }
]