bacnet-stack BACnet Stack up to 1.4.3rc1/1.5.0rc3 wp.c wp_decode_service_request out-of-bounds

Summaryinfo

A vulnerability categorized as problematic has been discovered in bacnet-stack BACnet Stack up to 1.4.3rc1/1.5.0rc3. The affected element is the function wp_decode_service_request of the file wp.c. Executing a manipulation can lead to out-of-bounds. The identification of this vulnerability is CVE-2026-26264. The attack may be launched remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in bacnet-stack BACnet Stack up to 1.4.3rc1/1.5.0rc3. This vulnerability affects the function wp_decode_service_request of the file wp.c. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-26264 since 02/12/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit.

Upgrading to version 1.4.3rc2 or 1.5.0rc4 eliminates this vulnerability. Applying the patch 4cc8067c86f26e2b08b2c8f4d27f8e07de4d4708 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• bacnet-stack

Name

• BACnet Stack

Version

• 1.4.3rc1
• 1.5.0rc1
• 1.5.0rc2
• 1.5.0rc3

License

• open-source

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