# CVE-2026-46674: BACnet Stack out-of-bounds read in AtomicWriteFile

Source: https://junglewise.ai/threats/cve-2026-46674-bacnet-stack-is-a-bacnet-open-source-protocol-stack-c-library-for  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-12. Updated: 2026-11-12  
License: CC BY 4.0 with a link back

CVE-2026-46674 · Severity: high · CVSS 7.5 · Published 2026-11-12

BACnet Stack is a protocol library used in building automation and industrial control systems. A vulnerability in its AtomicWriteFile request handler allows a remote attacker to read beyond allocated memory on the server, potentially causing system crashes or exposing sensitive data from memory. The flaw can be triggered by sending a crafted network message without authentication.

Technologies: [BACnet Stack Project BACnet Stack](https://junglewise.ai/threats/technologies/bacnet-stack). Vendors: [BACnet Stack Project](https://junglewise.ai/threats/vendors/bacnet-stack-project).

## Quick answers

**Is CVE-2026-46674 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-46674 being exploited in the wild.

**How severe is CVE-2026-46674?** High severity, with a CVSS score of 7.5, published 12 November 2026.

**Which products and versions are affected?** BACnet Stack Project BACnet Stack before 1.4.4 and 1.5.1.

**Is there a fix for CVE-2026-46674?** Yes: fixed in 1.4.4, 1.5.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-46674 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-46674?** Check whether you run BACnet Stack Project BACnet Stack at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.4.4, 1.5.1

## Technical details

An out-of-bounds read in the AtomicWriteFile record-access decoder (awf_decode_service_request) results from an externally controlled returnedRecordCount value that exceeds the fixed-size fileData[] array capacity (1 element by default in BACNET_ATOMIC_WRITE_FILE_DATA). The decoder accepts the oversized count without validation, and later code paths iterate using this untrusted count, accessing stack memory beyond the allocated structure. The vulnerability is reachable pre-authentication via network-facing BACnet service dispatch and is triggered by crafted incoming requests.

## Affected products

- BACnet Stack project BACnet Stack before 1.4.4 and 1.5.1

## Timeline

- 2026-11-12: disclosed
- 2026-05-13: patched

## References

- [https://github.com/bacnet-stack/bacnet-stack/pull/1344](https://github.com/bacnet-stack/bacnet-stack/pull/1344)
- [https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-8384-pwhh-cxjh](https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-8384-pwhh-cxjh)

## Related threats

- [BACnet Stack stack-buffer-overflow in Loop object property read](https://junglewise.ai/threats/cve-2026-47710-bacnet-stack-is-a-bacnet-open-source-protocol-stack-c-library-for)
- [BACnet Stack out-of-bounds read in bacnet_tag_number_decode](https://junglewise.ai/threats/cve-2026-38570-bacnet-stack-out-of-bounds-read-in-bacnet-tag-number-decode)