bacnet-stack: Stack-based Buffer Overflow
CVE-2026-45265 is a high-severity stack-based buffer overflow vulnerability in bacnet-stack, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected bacnet-stack versions: < 1.4.4; < 1.5.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.26% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of bacnet-stack you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Bacnet-stack | bacnet-stack | < 1.4.4; < 1.5.1 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- LowLimited modification of data is possible.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H. Scored by CNA (github.com).
Official description
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.4 and 1.5.1, there is a stack-based out-of-bounds write / stack-buffer-overflow in bacnet-stack when the server processes a malicious Atomic-Read-File request in record access mode. The bug is triggered on the real server side. A crafted request can set an excessively large RecordCount, which is later used as the loop bound for writing record data into a stack-allocated BACNET_ATOMIC_READ_FILE_DATA data structure. However, the stack object only has space for one fileData element. When the loop reaches i = 1, the code computes &data->fileData[1], which is already out of bounds, and the resulting invalid pointer is passed down to memmove(), causing a stack-buffer-overflow. This issue has been patched in versions 1.4.4 and 1.5.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Stack-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the stack.
How developers prevent this class of flaw
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implement and perform bounds checking on input.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in bacnet-stack
- 7.7 High severity
- 8.8 High severity
- 8.7 High severity
- 8.7 High severity
- 8.1 High severity
- 7.7 High severity
Recent Stack-based Buffer Overflow vulnerabilities
- 8.6 High severity
- 8.2 High severity
- 8.2 High severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
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