{"id":"CVE-2026-41502","summary":"BACnet Stack: Off-by-One Out-of-Bounds Read in ReadPropertyMultiple Object ID Decoder","details":"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 \u003c 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.","aliases":["GHSA-7545-3fpx-4xw3"],"modified":"2026-07-15T01:49:17.194841137Z","published":"2026-04-24T19:40:43.059Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-125","CWE-193"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41502.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41502.json"},{"type":"ADVISORY","url":"https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-7545-3fpx-4xw3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41502"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/bacnet-stack/bacnet-stack","events":[{"introduced":"f332225b196aa66503faae64f92bef113fe89ab2"},{"fixed":"6d2d251ca4f4d932664add702b236279863d630a"}],"database_specific":{"cpe":"cpe:2.3:a:bacnetstack:bacnet_stack:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"1.4.0"},{"fixed":"1.4.3"}],"source":["AFFECTED_FIELD","CPE_RANGE"]}}],"versions":["bacnet-stack-1.4.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-41502.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}