CVE-2026-48686_CVE-2026-48686

{
    "lastseen": "",
    "description": "FastNetMon Community Edition through 1.2.9 contains a stack-based buffer overflow in the BGP NLRI (Network Layer Reachability Information) decoder. The function decode_bgp_subnet_encoding_ipv4_raw() in src/bgp_protocol.cpp reads prefix_bit_length directly from the BGP packet (line 99) without validating it is <= 32 for IPv4 prefixes. This value is passed to how_much_bytes_we_need_for_storing_certain_subnet_mask() which computes ceil(prefix_bit_length / 8), returning up to 32 bytes for a prefix_bit_length of 255. The result is used as the length argument to memcpy() (line 106), which copies into a 4-byte uint32_t stack variable (prefix_ipv4). This causes a stack buffer overflow of up to 28 bytes, which can be exploited for arbitrary code execution. Additionally, the unvalidated prefix_bit_length is passed to convert_cidr_to_binary_netmask_local_function_copy() (line 111), where a shift of (32 - cidr) with cidr > 32 causes undefined behavior.",
    "published": "2026-05-26T00:00:00.000Z",
    "modified": "2026-05-26T20:59:11.887Z",
    "type": "cve",
    "title": "CVE-2026-48686",
    "source": "mitre",
    "references": "https://github.com/pavel-odintsov/fastnetmon\nhttps://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.cpp\nhttps://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48686-bgp-nlri-stack-overflow",
    "id": "CVE-2026-48686",
    "bulletinFamily": "",
    "cwe": [
        "CWE-787",
        "CWE-120"
    ],
    "cvelist": null,
    "sourceData": "n/a n/a n/a",
    "sourceHref": "",
    "cvss": {
        "score": 9.8,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
        "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": "FastNetMon Community Edition",
    "version": "1.2.9",
    "vendor": "Evil by Design",
    "ai_description": "Stack-based buffer overflow in BGP NLRI decoder",
    "ai_severity": "Critical",
    "ai_vendor": "Evil by Design",
    "ai_product": "FastNetMon Community Edition",
    "ai_version": "1.2.9",
    "ai_score": 9.8
}