CVE-2025-66624

BACnet Protocol Stack library provides a BACnet application layer, network layer and media access (MAC) layer communications services. Prior to 1.5.0.rc2, The npdu_is_expected_reply function in src/bacnet/npdu.c indexes request_pdu[offset+2/3/5] and reply_pdu[offset+1/2/4] without verifying that those APDU bytes exist. bacnet_npdu_decode() can return offset == 2 for a 2-byte NPDU, so tiny PDUs pass the version check and then get read out of bounds. On ASan/MPU/strict builds this is an immediate crash (DoS). On unprotected builds it is undefined behavior and can mis-route replies; RCE is unlikely because only reads occur, but DoS is reliable.

CVE ID:

CVE-2025-66624

Published:

2025-12-05

Modified:

2025-12-05

CVSS Score:

7.5

Severity:

HIGH

Vector:

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H