{"id":"CVE-2026-62976","summary":"BACnet Stack: Consecutive AtomicWriteFile(record-access) appends can trigger a heap out-of-bounds read in the RAMFS file backend","details":"BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to version 1.5.1, the RAMFS-backed FILE object implementation stores appended records as NUL-terminated strings, but its record-counting logic later walks the buffer as if an additional terminating empty record were present. As a result, two consecutive AtomicWriteFile(record-access) append requests can cause record_count() to call bacnet_strnlen() on a pointer that is already one byte past the end of the heap allocation. This issue has been patched in versions 1.5.1 and 1.6.0.","aliases":["GHSA-32jj-x86x-w98w"],"modified":"2026-11-14T10:45:15.598679430Z","published":"2026-11-13T18:39:25.636Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62976.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-125"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62976.json"},{"type":"FIX","url":"https://github.com/bacnet-stack/bacnet-stack/pull/1408"},{"type":"ADVISORY","url":"https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-32jj-x86x-w98w"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-62976"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/bacnet-stack/bacnet-stack","events":[{"introduced":"0"},{"fixed":"3a74c74a8139526e34da32c6cc41ed7c71aaded5"}],"database_specific":{"extracted_events":[{"range":[{"introduced":"0"},{"fixed":"1.5.1"}],"source":"AFFECTED_FIELD","strategy":"StringRangeExpression"}]}}],"versions":["bacnet-stack-1.5.0","bacnet-stack-1.4.2","bacnet-stack-1.4.1","bacnet-stack-1.4.0","bacnet-stack-1.3.8","bacnet-stack-1.3.7","bacnet-stack-1.3.6","bacnet-stack-1.3.5","bacnet-stack-1.3.4","bacnet-stack-1.3.3","bacnet-stack-1.3.2","bacnet-stack-1.3.1","bacnet-stack-1.3.0","bacnet-stack-1.2.0","bacnet-stack-1.1.1","bacnet-stack-1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-62976.json"}}],"schema_version":"1.9.2","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"}]}