CVSS 4.0
6.9 mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NCVE-2026-62975 BACnet Stack: Replacing a RAMFS record with a shorter one via `AtomicWriteFile(record-access)` can trigger a heap out-of-bounds read
Medium (6.9) in bacnet-stack bacnet-stack.
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BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to version 1.5.1, the RAMFS-backed FILE implementation accepts AtomicWriteFile(record-access) requests that replace existing records with caller-controlled content. If a client replaces a record with shorter data, the backend can shrink the heap allocation and then continue processing with a trailing-copy length derived from the old layout. During that replace path, the RAMFS backend computes the trailing-copy length from the old file layout, then shrinks the heap allocation, and finally uses the stale length in memmove(). As a result, the source range of that memmove() can extend beyond the end of the reallocated heap buffer, producing a heap out-of-bounds read. This issue has been patched in versions 1.5.1 and 1.6.0.
Severity
- CWE
- CWE-125 Out-of-bounds Read
- Published
- Modified
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| bacnet-stack | < 1.5.1 |
Attack patterns (CAPEC)
- CAPEC-540 Overread Buffers Likelihood: Low · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.