BACnet Stack WriteProperty decoding length underflow leads to OOB read and crash_CVE-2026-26264

{
    "lastseen": "",
    "description": "BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.5.0rc4 and 1.4.3rc2, a malformed WriteProperty request can trigger a length underflow in the BACnet stack, leading to an out\u2011of\u2011bounds read and a crash (DoS). The issue is in wp.c within wp_decode_service_request. When decoding the optional priority context tag, the code passes apdu_len - apdu_size to bacnet_unsigned_context_decode without validating that apdu_size <= apdu_len. If a truncated APDU reaches this path, apdu_len - apdu_size underflows, resulting in a large size being used for decoding and an out\u2011of\u2011bounds read. This vulnerability is fixed in 1.5.0rc4 and 1.4.3rc2.",
    "published": "2026-02-13T18:14:30.232Z",
    "modified": "2026-02-13T18:14:30.232Z",
    "type": "cve",
    "title": "BACnet Stack WriteProperty decoding length underflow leads to OOB read and crash",
    "source": "GitHub_M",
    "references": "https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-phjh-v45p-gmjj\nhttps://github.com/bacnet-stack/bacnet-stack/commit/4cc8067c86f26e2b08b2c8f4d27f8e07de4d4708",
    "id": "CVE-2026-26264",
    "bulletinFamily": "",
    "cwe": [
        "CWE-125"
    ],
    "cvelist": null,
    "sourceData": "bacnet-stack bacnet-stack >= 1.5.0rc1, < 1.5.0rc4\nbacnet-stack bacnet-stack < 1.4.3rc2",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:P",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
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        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
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        "availabilityImpact": "",
        "cvssV3": {
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "bacnet-stack",
    "version": ">= 1.5.0rc1, < 1.5.0rc4",
    "vendor": "bacnet-stack",
    "ai_description": "",
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    "ai_score": 0
}