# CVE-2026-102537: bacnet-stack BACnet/SC node always accepts a self-signed hub cert, so an attacker can MITM it

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

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.6, 1.5.2, and 1.6.1, bws_cli_connect() in ports/linux/websocket-cli.c loads the trusted CA cert into the libwebsockets context, then always sets LCCSCF_ALLOW_SELFSIGNED in the connection flags. So lws accepts any self-signed hub certificate, whether or not it chains to the loaded CA. A BACnet/SC node finishes the TLS handshake to a rogue hub that presents a self-signed cert. It then hands the attacker its identity (VMAC, UUID) and all later BACnet traffic. This issue has been patched in versions 1.4.6, 1.5.2, 1.6.1, and 1.7.0.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- bacnet-stack / bacnet-stack: < 1.4.6 (affected); >= 1.5.0, < 1.5.2 (affected); >= 1.6.0, < 1.6.1 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 7.7 (high); CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-295

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-jgm4-2wg9-jwfg (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/bacnet-stack/bacnet-stack/pull/1434 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-102537; retrieved 2026-11-13; source updated 2026-11-13

Revision: 177301f5be696e67aaea77a465c3d18678bc5a68fc016053820edff23917c019

Canonical: https://y2.dev/cve/CVE-2026-102537

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