Handler on Duty: Jesse La Grew
Threat Level: green
| Published | 2026-04-24 20:16:28 |
|---|---|
| Last Modified | 2026-04-24 20:16:28 |
| AKA | CVE-2026-41502 |
| Summary | BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an off-by-one out-of-bounds read vulnerability in bacnet-stack's ReadPropertyMultiple service decoder allows unauthenticated remote attackers to read one byte past an allocated buffer boundary by sending a crafted RPM request with a truncated object identifier. The vulnerability is in rpm_decode_object_id(), which checks apdu_len < 5 but then accesses all 6 byte positions (indices 0-5) — consuming 1 byte for the context tag, 4 bytes for the object ID, then reading apdu[5] for the opening tag check. A 5-byte input passes the length check but causes a 1-byte OOB read, 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. |
| Access Vector | Local | Adjacent | Network |
|---|---|---|---|
| Access Complexity | Low | Medium | High |
| Authentication | None | Single | Multiple |
| Confidentiality | None | Partial | Complete |
| Integrity | None | Partial | Complete |
| Availability | None | Partial | Complete |