Bacnet-stack: Out-of-bounds Read (CVE-2026-46677)
Published Last modified Sources: CVE.org, EUVD
What is affected, what to do
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 client-side out-of-bounds read in the AtomicReadFile-ACK record-access handling path.
Update Bacnet-stack to version 1.4.4, Bacnet-stack to version 1.5.1.
- Affected
- Bacnet-stack
lt *..1.4.4 - Bacnet-stack
lt *..1.5.1
- Bacnet-stack
- Fixed in
- Bacnet-stack
1.4.4 - Bacnet-stack
1.5.1
- Bacnet-stack
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Metrics
6.5
XIEM Effective CVSS
Highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
6.5
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: CVE.org, EUVD
—
EPSS score
No value is available for this vulnerability.
Show all metrics
- Severity
- Medium
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 62.50 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 6.5 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 6.5
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-125, CWE-130
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
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 client-side out-of-bounds read in the AtomicReadFile-ACK record-access handling path. The issue is caused by a mismatch between a remote returnedRecordCount value and the fixed local fileData[] array capacity in BACNET_ATOMIC_READ_FILE_DATA. The ACK decode path preserves the remote RecordCount, discards storage for excess records without truncating that count, and a downstream sink later iterates over the original RecordCount and indexes fileData[i] out of bounds. This issue has been patched in versions 1.4.4 and 1.5.1.
Source: NVD (NIST), cvelistv5, ENISA EUVD, CVE.org (MITRE)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| bacnet-stack | bacnet-stack |
|
|
Vendors and products
Weakness classes (CWE)
CWE-125Out-of-bounds Read
Base
The product reads data past the end, or before the beginning, of the intended buffer.
Entry at MITRE CWE-125CWE-130Improper Handling of Length Parameter Inconsistency
Base
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
Entry at MITRE CWE-130
References & sources
- github.combacnet-stack/bacnet-stack/pull/1344x_refsource_MISC, euvd
- github.combacnet-stack/bacnet-stack/security/advisories/GHSA-rv5h-cxwq-q3…x_refsource_CONFIRM, euvd
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
ReceivedGitHub
CVSS V3.1: AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness type: CWE-125, CWE-130
Description added or changed
Show 7 original changes
Individual changes of this event as published by NVD Type Action Before After Description added —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 client-side out-of-bounds read in the AtomicReadFile-ACK record-access handling path. The issue is caused by a mismatch between a remote returnedRecordCount value and the fixed local fileData[] array capacity in BACNET_ATOMIC_READ_FILE_DATA. The ACK decode path preserves the remote RecordCount, discards storage for excess records without truncating that count, and a downstream sink later iterates over the original RecordCount and indexes fileData[i] out of bounds. This issue has been patched in versions 1.4.4 and 1.5.1.CVSS added —AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:HWeakness type (CWE) added —CWE-125Weakness type (CWE) added —CWE-130Affected versions (publisher) added —New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/46xxx/CVE-2026-46677.json">CVE-2026-46677</a>Reference added —https://github.com/bacnet-stack/bacnet-stack/pull/1344Reference added —https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-rv5h-cxwq-q3mhSource identifier: security-advisories@github.com
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<a href="https://intel.neosec.eu/en/cve/CVE-2026-46677"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-46677.svg?lang=en" alt="CVE-2026-46677 – NEOSEC Intel" height="20"></a>