EUVD-2026-24166Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Lifecycle Timeline
6DescriptionGitHub Advisory
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, decode_signed32() in src/bacnet/bacint.c reconstructs a 32-bit signed integer from four APDU bytes using signed left shifts. When any of the four bytes has bit 7 set (value ≥ 0x80), the left-shift operation overflows a signed int32_t, which is undefined behavior per the C standard. This is flagged thousands of times per minute by UndefinedBehaviorSanitizer on any BACnet input containing signed-integer property values with high-bit-set bytes. This vulnerability is fixed in 1.4.3.
AnalysisAI
BACnet Stack prior to version 1.4.3 exhibits undefined behavior in the decode_signed32() function when processing signed-integer property values containing bytes with the high bit set, causing denial of service through integer overflow. Network-remote attackers can trigger this vulnerability by sending specially crafted BACnet packets with high-bit-set byte sequences, resulting in application instability or crash on embedded systems running vulnerable versions. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Attacker must be network-reachable to the BACnet Stack instance (implying BACnet service port exposure, typically UDP port 47808). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 3.7 with AV:N/AC:H indicates network-remote attack vector but requires high attack complexity, suggesting non-trivial exploitation constraints. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker on the network sends a BACnet frame containing a signed-integer property value with bytes having bit 7 set (e.g., 0x80 or higher). The vulnerable decode_signed32() function processes this frame, triggering a signed left-shift integer overflow that violates C standard undefined behavior. … |
| Remediation | Upgrade BACnet Stack to version 1.4.3 or later, which corrects the signed integer overflow in decode_signed32(). … Detailed patch versions, workarounds, and compensating controls in full report. |
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