BACnet Stack: Out-of-Bounds Read in ReadPropertyMultiple Property Decoder via Deprecated Tag Parser_CVE-2026-41503

{
    "lastseen": "",
    "description": "BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an out-of-bounds read vulnerability in bacnet-stack's ReadPropertyMultiple service property decoder allows unauthenticated remote attackers to read past allocated buffer boundaries by sending an RPM request with a truncated property list. The vulnerability stems from rpm_decode_object_property() calling the deprecated decode_tag_number_and_value() function at src/bacnet/rpm.c:344, which accepts no buffer length parameter and reads blindly from whatever pointer it receives. A crafted BACnet/IP packet with a 1-byte property payload containing an extended tag marker (0xF9) causes the decoder to read 1 byte past the end of the buffer, leading to crashes on embedded BACnet devices. The vulnerability exists in src/bacnet/rpm.c and affects any deployment that enables the ReadPropertyMultiple confirmed service handler (enabled by default in the reference server). This vulnerability is fixed in 1.4.3.",
    "published": "2026-04-24T19:41:44.071Z",
    "modified": "2026-04-24T19:41:44.071Z",
    "type": "cve",
    "title": "BACnet Stack: Out-of-Bounds Read in ReadPropertyMultiple Property Decoder via Deprecated Tag Parser",
    "source": "GitHub_M",
    "references": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-5w2v-mwqj-pr2c",
    "id": "CVE-2026-41503",
    "bulletinFamily": "",
    "cwe": [
        "CWE-125"
    ],
    "cvelist": null,
    "sourceData": "bacnet-stack bacnet-stack >= 1.4.0, < 1.4.3",
    "sourceHref": "",
    "cvss": {
        "score": 8.7,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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            "confidentialityImpact": "",
            "integrityImpact": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "bacnet-stack",
    "version": ">= 1.4.0, < 1.4.3",
    "vendor": "bacnet-stack",
    "ai_description": "Out-of-bounds read vulnerability in ReadPropertyMultiple service property decoder",
    "ai_severity": "High",
    "ai_vendor": "BACnet Stack",
    "ai_product": "BACnet Stack",
    "ai_version": "1.4.0 to 1.4.2",
    "ai_score": 8.7
}