{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-21870",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-01-05T16:44:16.368Z",
        "datePublished": "2026-02-13T17:58:37.205Z",
        "dateUpdated": "2026-02-13T18:19:36.183Z"
    },
    "containers": {
        "cna": {
            "title": "The BACnet Protocol Stack library has an Off-by-one Stack-based Buffer Overflow in tokenizer_string",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-193",
                            "lang": "en",
                            "description": "CWE-193: Off-by-one Error",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "LOCAL",
                        "availabilityImpact": "HIGH",
                        "baseScore": 5.5,
                        "baseSeverity": "MEDIUM",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "REQUIRED",
                        "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx"
                },
                {
                    "name": "https://github.com/bacnet-stack/bacnet-stack/pull/1196",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/bacnet-stack/bacnet-stack/pull/1196"
                },
                {
                    "name": "https://github.com/bacnet-stack/bacnet-stack/commit/4e1176394a5ae50d2fd0b5790d9bff806dc08465",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/bacnet-stack/bacnet-stack/commit/4e1176394a5ae50d2fd0b5790d9bff806dc08465"
                }
            ],
            "affected": [
                {
                    "vendor": "bacnet-stack",
                    "product": "bacnet-stack",
                    "versions": [
                        {
                            "version": "<= 1.4.2",
                            "status": "affected"
                        },
                        {
                            "version": ">= 1.5.0.rc1, <= 1.5.0.rc2",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-02-13T17:58:37.205Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "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."
                }
            ],
            "source": {
                "advisory": "GHSA-pc83-wp6w-93mx",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-02-13T18:19:25.750164Z",
                                "id": "CVE-2026-21870",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-02-13T18:19:36.183Z"
                }
            }
        ]
    }
}