CVE-2026-41503
Severity CVSS v4.0:
HIGH
Type:
CWE-125
Out-of-bounds Read
Publication date:
24/04/2026
Last modified:
28/04/2026
Description
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an out-of-bounds read vulnerability in bacnet-stack's ReadPropertyMultiple service property decoder allows unauthenticated remote attackers to read past allocated buffer boundaries by sending an RPM request with a truncated property list. The vulnerability stems from rpm_decode_object_property() calling the deprecated decode_tag_number_and_value() function at src/bacnet/rpm.c:344, which accepts no buffer length parameter and reads blindly from whatever pointer it receives. A crafted BACnet/IP packet with a 1-byte property payload containing an extended tag marker (0xF9) causes the decoder to read 1 byte past the end of the buffer, 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.
Impact
Base Score 4.0
8.70
Severity 4.0
HIGH
Base Score 3.x
7.50
Severity 3.x
HIGH
Vulnerable products and versions
| CPE | From | Up to |
|---|---|---|
| cpe:2.3:a:bacnetstack:bacnet_stack:*:*:*:*:*:*:*:* | 1.4.0 (including) | 1.4.3 (excluding) |
| cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc1:*:*:*:*:*:* |
To consult the complete list of CPE names with products and versions, see this page