{
    "id": "CVE-2021-27137",
    "published": "2026-07-16 18:16:39",
    "last_modified": "2026-07-22 05:17:07",
    "cvss_score": "8.1",
    "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:H",
    "cwe": "CWE-121",
    "description": "An issue was discovered in router/upnp/src/ssdp.c in DD-WRT before 45724. An unsafe strcpy in the UPnP handling functionality allows an unauthenticated remote attacker to send a request that would overflow an internal fixed buffer. Exploitation requires the DD-WRT user to enable UPnP (which is off by default, and only listens on internal interfaces by default). This occurs in ssdp_msearch (reachable by an M-SEARCH request).",
    "epss_score": "0.03995",
    "epss_percentile": "0.90167",
    "kev": 1,
    "kev_due": "2026-07-24",
    "has_exploit": 0,
    "updated_at": "2026-09-27 18:17:29",
    "priority": {
        "rank": 1,
        "label": "Patch first",
        "why": "On CISA KEV — known exploited in the wild, due 2026-07-24."
    },
    "products": [
        {
            "vendor": "dd-wrt",
            "product": "dd-wrt"
        }
    ],
    "kev_detail": {
        "cve_id": "CVE-2021-27137",
        "date_added": "2026-07-21",
        "due_date": "2026-07-24",
        "vendor": "DD-WRT",
        "product": "DD-WRT",
        "name": "DD-WRT Stack-Based Buffer Overflow Vulnerability",
        "ransomware": 0
    },
    "exploits": [],
    "refs_list": [
        "https://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competitor-killing-capability.html",
        "https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/",
        "https://svn.dd-wrt.com/changeset/45724",
        "https://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-router-flaw-kills-rival-malware/",
        "https://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-of-new-gafgyt-variant-c0xmo",
        "https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/",
        "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27137"
    ]
}