CVE-2026-21870

{"id": "CVE-2026-21870", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "published": "2026-02-13T18:16:19.783", "references": [{"url": "https://github.com/bacnet-stack/bacnet-stack/commit/4e1176394a5ae50d2fd0b5790d9bff806dc08465", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/bacnet-stack/bacnet-stack/pull/1196", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx", "tags": ["Vendor Advisory", "Exploit"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-193"}]}], "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."}], "lastModified": "2026-02-18T18:49:07.307", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:bacnetstack:bacnet_stack:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3BF2BFCC-54CE-412E-947A-B5C834161829", "versionEndIncluding": "1.4.2"}, {"criteria": "cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "2B47182E-6B7F-4C53-904A-EB37C9C0A439"}, {"criteria": "cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CF491863-1A31-4A23-A6AC-DF7545FCAA48"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}