CVE-2026-62976
BACnet Stack: Consecutive AtomicWriteFile(record-access) appends can trigger a heap out-of-bounds read in the RAMFS file backend
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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| bacnet-stack bacnet-stack |
< 1.5.1 (affected) | CNA: GitHub_M |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.7 high |
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 | CNA: GitHub_M |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-32jj-x86x-w98wCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/bacnet-stack/bacnet-stack/pull/1408CNA: GitHub_M · x_refsource_MISC
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