{
    "id": "CVE-2021-23017",
    "published": "2021-06-01 13:15:07",
    "last_modified": "2026-06-17 03:38:13",
    "cvss_score": "7.7",
    "cvss_severity": "HIGH",
    "cvss_version": "3.1",
    "cvss_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L",
    "cwe": "CWE-193",
    "description": "A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause 1-byte memory overwrite, resulting in worker process crash or potential other impact.",
    "epss_score": "0.53461",
    "epss_percentile": "0.98958",
    "kev": 0,
    "kev_due": null,
    "has_exploit": 1,
    "updated_at": "2026-09-26 18:27:30",
    "priority": {
        "rank": 2,
        "label": "Patch early",
        "why": "A public exploit exists."
    },
    "products": [
        {
            "vendor": "f5",
            "product": "nginx"
        },
        {
            "vendor": "fedoraproject",
            "product": "fedora"
        },
        {
            "vendor": "netapp",
            "product": "ontap_select_deploy_administration_utility"
        },
        {
            "vendor": "openresty",
            "product": "openresty"
        },
        {
            "vendor": "oracle",
            "product": "blockchain_platform"
        },
        {
            "vendor": "oracle",
            "product": "communications_control_plane_monitor"
        },
        {
            "vendor": "oracle",
            "product": "communications_fraud_monitor"
        },
        {
            "vendor": "oracle",
            "product": "communications_operations_monitor"
        },
        {
            "vendor": "oracle",
            "product": "communications_session_border_controller"
        },
        {
            "vendor": "oracle",
            "product": "enterprise_communications_broker"
        },
        {
            "vendor": "oracle",
            "product": "enterprise_session_border_controller"
        },
        {
            "vendor": "oracle",
            "product": "enterprise_telephony_fraud_monitor"
        },
        {
            "vendor": "oracle",
            "product": "goldengate"
        }
    ],
    "kev_detail": null,
    "exploits": [
        {
            "source": "exploit-db",
            "ref_id": "50973",
            "title": "Nginx 1.20.0 - Denial of Service (DOS)",
            "date": "2022-07-11",
            "url": "https://www.exploit-db.com/exploits/50973"
        }
    ],
    "refs_list": [
        "http://mailman.nginx.org/pipermail/nginx-announce/2021/000300.html",
        "http://packetstormsecurity.com/files/167720/Nginx-1.20.0-Denial-Of-Service.html",
        "https://lists.apache.org/thread.html/r37e6b2165f7c910d8e15fd54f4697857619ad2625f56583802004009%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.apache.org/thread.html/r4d4966221ca399ce948ef34884652265729d7d9ef8179c78d7f17e7f%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.apache.org/thread.html/r6fc5c57b38e93e36213e9a18c8a4e5dbd5ced1c7e57f08a1735975ba%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.apache.org/thread.html/rf232eecd47fdc44520192810560303073cefd684b321f85e311bad31%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.apache.org/thread.html/rf318aeeb4d7a3a312734780b47de83cefb7e6995da0b2cae5c28675c%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7SFVYHC7OXTEO4SMBWXDVK6E5IMEYMEE/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNKOP2JR5L7KCIZTJRZDCUPJTUONMC5I/",
        "https://security.netapp.com/advisory/ntap-20210708-0006/",
        "https://support.f5.com/csp/article/K12331123%2C",
        "https://www.oracle.com/security-alerts/cpuapr2022.html",
        "https://www.oracle.com/security-alerts/cpujan2022.html",
        "https://www.oracle.com/security-alerts/cpuoct2021.html",
        "http://mailman.nginx.org/pipermail/nginx-announce/2021/000300.html",
        "http://packetstormsecurity.com/files/167720/Nginx-1.20.0-Denial-Of-Service.html",
        "https://lists.apache.org/thread.html/r37e6b2165f7c910d8e15fd54f4697857619ad2625f56583802004009%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.apache.org/thread.html/r4d4966221ca399ce948ef34884652265729d7d9ef8179c78d7f17e7f%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.apache.org/thread.html/r6fc5c57b38e93e36213e9a18c8a4e5dbd5ced1c7e57f08a1735975ba%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.apache.org/thread.html/rf232eecd47fdc44520192810560303073cefd684b321f85e311bad31%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.apache.org/thread.html/rf318aeeb4d7a3a312734780b47de83cefb7e6995da0b2cae5c28675c%40%3Cnotifications.apisix.apache.org%3E",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7SFVYHC7OXTEO4SMBWXDVK6E5IMEYMEE/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNKOP2JR5L7KCIZTJRZDCUPJTUONMC5I/",
        "https://security.netapp.com/advisory/ntap-20210708-0006/",
        "https://support.f5.com/csp/article/K12331123%2C"
    ]
}