bacnet-stack: Always-Incorrect Control Flow Implementation
CVE-2026-47257 is a high-severity always-incorrect control flow implementation vulnerability in bacnet-stack, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected bacnet-stack versions: >= 1.5.0, < 1.5.1; >= 1.6.0-rc1, < 1.6.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.39% 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.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Bacnet-stack | bacnet-stack | >= 1.5.0, < 1.5.1; >= 1.6.0-rc1, < 1.6.0 | 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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H. Scored by CNA (github.com).
Official description
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. In versions 1.5.0 and 1.6.0-rc1, there is a restore logic flaw in bacnet-stack that is reachable through the official, unmodified apps/server management path when BACNET_BACKUP_RESTORE is enabled. This issue has been patched in versions 1.5.1 and 1.6.0.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Always-Incorrect Control Flow Implementation
The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated.
More Always-Incorrect Control Flow Implementation vulnerabilities (CWE-670)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, 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 Always-Incorrect Control Flow Implementation vulnerabilities
- 9.8 Critical severity
- 8.1 High severity
- 7.5 High severity
- 7.8 High severity
- 9.1 Critical severity
- 7.3 High severity
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