{"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"}}]}}

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