Vulnerability Instance

HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "url": "http://public2.vulnerablecode.io/api/vulnerabilities/74409?format=api",
    "vulnerability_id": "VCID-hm83-nh9x-27ay",
    "summary": "BACnet Protocol Stack library provides a BACnet application layer, network layer and media access (MAC) layer communications services. In 1.4.2, 1.5.0.rc2, and earlier, an off-by-one stack-based buffer overflow in the ubasic interpreter causes a crash (SIGABRT) when processing string literals longer than the buffer limit. The tokenizer_string function in src/bacnet/basic/program/ubasic/tokenizer.c incorrectly handles null termination for maximum-length strings. It writes a null byte to dest[40] when the buffer size is only 40 (indices 0-39), triggering a stack overflow.",
    "aliases": [
        {
            "alias": "CVE-2026-21870"
        }
    ],
    "fixed_packages": [],
    "affected_packages": [],
    "references": [
        {
            "reference_url": "https://api.first.org/data/v1/epss?cve=CVE-2026-21870",
            "reference_id": "",
            "reference_type": "",
            "scores": [
                {
                    "value": "7e-05",
                    "scoring_system": "epss",
                    "scoring_elements": "0.00531",
                    "published_at": "2026-06-11T12:55:00Z"
                },
                {
                    "value": "7e-05",
                    "scoring_system": "epss",
                    "scoring_elements": "0.0053",
                    "published_at": "2026-06-13T12:55:00Z"
                },
                {
                    "value": "7e-05",
                    "scoring_system": "epss",
                    "scoring_elements": "0.00528",
                    "published_at": "2026-06-12T12:55:00Z"
                }
            ],
            "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-21870"
        },
        {
            "reference_url": "https://github.com/bacnet-stack/bacnet-stack/pull/1196",
            "reference_id": "1196",
            "reference_type": "",
            "scores": [
                {
                    "value": "5.5",
                    "scoring_system": "cvssv3.1",
                    "scoring_elements": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
                },
                {
                    "value": "Track",
                    "scoring_system": "ssvc",
                    "scoring_elements": "SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-02-13T18:19:25Z/"
                }
            ],
            "url": "https://github.com/bacnet-stack/bacnet-stack/pull/1196"
        },
        {
            "reference_url": "https://github.com/bacnet-stack/bacnet-stack/commit/4e1176394a5ae50d2fd0b5790d9bff806dc08465",
            "reference_id": "4e1176394a5ae50d2fd0b5790d9bff806dc08465",
            "reference_type": "",
            "scores": [
                {
                    "value": "5.5",
                    "scoring_system": "cvssv3.1",
                    "scoring_elements": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
                },
                {
                    "value": "Track",
                    "scoring_system": "ssvc",
                    "scoring_elements": "SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-02-13T18:19:25Z/"
                }
            ],
            "url": "https://github.com/bacnet-stack/bacnet-stack/commit/4e1176394a5ae50d2fd0b5790d9bff806dc08465"
        },
        {
            "reference_url": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx",
            "reference_id": "GHSA-pc83-wp6w-93mx",
            "reference_type": "",
            "scores": [
                {
                    "value": "5.5",
                    "scoring_system": "cvssv3.1",
                    "scoring_elements": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
                },
                {
                    "value": "Track",
                    "scoring_system": "ssvc",
                    "scoring_elements": "SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-02-13T18:19:25Z/"
                }
            ],
            "url": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx"
        }
    ],
    "weaknesses": [
        {
            "cwe_id": 193,
            "name": "Off-by-one Error",
            "description": "A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value."
        }
    ],
    "exploits": [],
    "severity_range_score": "5.5 - 5.5",
    "exploitability": null,
    "weighted_severity": null,
    "risk_score": null,
    "resource_url": "http://public2.vulnerablecode.io/vulnerabilities/VCID-hm83-nh9x-27ay"
}