CVE-2026-49990
BACnet Stack: AtomicReadFile/AtomicWriteFile stream fileStartPosition validation flaw causes out-of-bounds read/write in RAM file backends
CVSS Score
8.6
EPSS Score
0.0%
EPSS Percentile
0th
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. From versions 1.4.2 to before 1.4.5, and 1.5.0 to before 1.5.1, a signed fileStartPosition taken from AtomicReadFile and AtomicWriteFile stream-access requests is not validated tightly enough before it reaches the RAM file backends. Practical impact includes: reliable denial of service via process crash, out-of-bounds read that may expose adjacent memory contents, or out-of-bounds write that may corrupt heap memory and destabilize the process. This issue has been patched in versions 1.4.5 and 1.5.1.
| CWE | CWE-125 CWE-787 |
| Vendor | bacnet-stack |
| Product | bacnet-stack |
| Published | Nov 13, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
High
Affected Versions
bacnet-stack / bacnet-stack
>= 1.4.2, < 1.4.5 >= 1.5.0, < 1.5.1