CVE-2026-26264

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‑of‑bounds 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‑of‑bounds read. This vulnerability is fixed in 1.5.0rc4 and 1.4.3rc2.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/bacnet-stack/bacnet-stack/commit/4cc8067c86f26e2b08b2c8f4d27f8e07de4d4708	Patch
https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-phjh-v45p-gmjj	Vendor Advisory Exploit

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:bacnetstack:bacnet_stack::::::::
	cpe:2.3:a:bacnetstack:bacnet_stack:1.4.3:rc1::::::
	cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc1::::::
	cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc2::::::
	cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc3::::::

History

No history.

Information

Published : 2026-02-13 19:17

Updated : 2026-02-18 18:48

NVD link : CVE-2026-26264

Mitre link : CVE-2026-26264

CVE.ORG link : CVE-2026-26264

JSON object : View

Products Affected

bacnetstack

bacnet_stack

CWE

CWE-125

Out-of-bounds Read

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El problema est\u00e1 en wp.c dentro de wp_decode_service_request. Al decodificar la etiqueta de contexto de prioridad opcional, el c\u00f3digo pasa apdu_len - apdu_size a bacnet_unsigned_context_decode sin validar que apdu_size <= apdu_len. Si una APDU truncada alcanza esta ruta, apdu_len - apdu_size sufre un desbordamiento negativo, lo que resulta en un tama\u00f1o grande siendo utilizado para la decodificaci\u00f3n y una lectura fuera de l\u00edmites. 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