# CVE-2026-46674: BACnet Stack: Out-of-Bounds Read in AtomicWriteFile Record Decoder via Unbounded returnedRecordCount

Status: published. Published: 2026-11-12. Updated: 2026-11-13.

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.4 and 1.5.1, an out-of-bounds read vulnerability exists in bacnet-stack's AtomicWriteFile record-access path. The bug is caused by a mismatch between an externally controlled returnedRecordCount field and the fixed-size internal fileData[] array used by BACNET_ATOMIC_WRITE_FILE_DATA. This issue has been patched in versions 1.4.4 and 1.5.1.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- bacnet-stack / bacnet-stack: < 1.4.4 (affected); < 1.5.1 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: GitHub_M

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation poc; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-121, CWE-125

## Exploit evidence

- exploit: https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-8384-pwhh-cxjh (ADP: CISA-ADP)

## References

- https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-8384-pwhh-cxjh (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/bacnet-stack/bacnet-stack/pull/1344 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-8384-pwhh-cxjh (ADP: CISA-ADP; exploit)

- https://github.com/bacnet-stack/bacnet-stack/pull/1344 (security-advisories@github.com)

- https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-8384-pwhh-cxjh (security-advisories@github.com)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-46674; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46674; retrieved 2026-11-13; source updated 2026-11-12

Revision: afa35bbda0dd4c8e94d2d1f10495a2efe30b9a1c34b897097c4a258d9c8d9c08

Canonical: https://y2.dev/cve/CVE-2026-46674

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.