CVE-2026-27873 in EasyIO FG
Summary
by MITRE • 10/02/2026
- Use of Hard-coded Credentials vulnerability in Johnson Controls EasyIO FG allows - Pasword Spraying.
This issue affects EasyIO FG: before 2.0b52.
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Analysis
by VulDB Data Team • 10/02/2026
The identified security flaw within the Johnson Controls EasyIO FG firmware, specifically prior to version 2.0b52, constitutes a critical vulnerability rooted in the improper handling of authentication credentials. This issue is classified under Common Weakness Enumeration as CWE-798: Use of Hard-coded Credentials. The core technical deficiency lies in the embedding of static username and password pairs directly within the firmware binary or configuration files rather than utilizing dynamic credential generation or secure storage mechanisms such as hardware security modules or encrypted key stores. These hard-coded credentials are often present for initial setup, factory reset procedures, or remote maintenance access, but their presence creates a persistent attack surface that remains unchanged across all deployed units of this specific software version range.
The operational impact of this vulnerability is severe due to its facilitation of password spraying attacks. Password spraying involves an attacker attempting to log in with a single common username against many different passwords, or conversely, using a small set of known default credentials against multiple targets. In the context of EasyIO FG devices, which are often deployed in large numbers within industrial control systems and building automation networks, attackers can leverage publicly available lists of default hard-coded credentials to gain unauthorized access. Because these credentials do not expire and cannot be changed by standard user configuration interfaces prior to version 2.0b52, the window for exploitation is effectively infinite until a patch or manual intervention occurs. This lack of credential rotation capability means that once a specific device model's default password is identified through reconnaissance or leaked databases, it can be used to compromise any instance of EasyIO FG running an affected firmware version without requiring brute-force efforts against strong passwords.
From a tactical perspective, this vulnerability aligns with the MITRE ATT&CK technique T1078: Valid Accounts, specifically within the context of default accounts that are known and easily discoverable. An adversary exploiting this flaw would likely engage in initial access activities by scanning network segments for EasyIO FG devices using common service ports associated with industrial protocols or web interfaces. Upon identifying a target, the attacker would attempt authentication using the hard-coded credentials. Successful exploitation grants the attacker full administrative privileges over the device, allowing them to modify system configurations, intercept data flows, and potentially pivot into broader operational technology networks. This compromises the confidentiality, integrity, and availability of the connected systems, which may include HVAC controls, security sensors, or other critical infrastructure components managed by Johnson Controls equipment.
Mitigation strategies must prioritize immediate remediation through firmware updates. Organizations operating EasyIO FG devices should upgrade to version 2.0b52 or later, where these hard-coded credentials have been removed or replaced with secure, unique initialization processes that require the administrator to set a strong password during first-time setup. For systems that cannot be immediately updated due to operational constraints, network segmentation is essential. The EasyIO FG devices should be isolated in dedicated VLANs separate from general corporate IT networks and critical production zones. Access control lists on firewalls and switches must restrict inbound connections to these devices only from authorized management stations using strict IP whitelisting. Additionally, continuous monitoring for anomalous authentication attempts or unusual network traffic patterns originating from the industrial subnet can help detect exploitation activities early. Regular vulnerability assessments should include specific checks for default credentials in all IoT and OT assets to ensure no legacy configurations remain exposed.