CyberSecBulletin
CVE-2026-102537NVD status: Awaiting Analysis

bacnet-stack: Improper Certificate Validation

Published Updated By the CyberSecBulletin desk

CVE-2026-102537 is a high-severity improper certificate validation vulnerability in bacnet-stack, with a CVSS 4.0 base score of 7.7 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected bacnet-stack versions: < 1.4.6; >= 1.5.0, < 1.5.2; >= 1.6.0, < 1.6.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of bacnet-stack you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Bacnet-stackbacnet-stack< 1.4.6; >= 1.5.0, < 1.5.2; >= 1.6.0, < 1.6.1Not 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
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Attack requirements
PresentThe target must be in a specific state or configuration for the attack to work.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
HighSerious loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
HighSerious loss of integrity on the vulnerable system.
Availability (vulnerable system)
HighSerious loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
NoneNo loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
NoneNo loss of availability on systems beyond the vulnerable one.

Vector: 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (github.com).

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Certificate Validation

The product does not validate, or incorrectly validates, a certificate.

How developers prevent this class of flaw

  • Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
  • If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.

More Improper Certificate Validation vulnerabilities (CWE-295)

Timeline

  1. CVE record published.

References

Other vulnerabilities in bacnet-stack

All bacnet-stack vulnerabilities

Recent Improper Certificate Validation vulnerabilities

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