CVE-2026-41021 in easyE4
Summary
by MITRE • 10/27/2026
Eaton easyE4 uses an insufficiently strong password policy. An attacker who obtains a password hash, including through CVE-2026-41020, could perform an offline password-guessing attack and potentially recover user credentials.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability identified in Eaton's easyE4 programmable logic controller stems from the implementation of an insufficiently strong password policy within its authentication mechanism. This architectural weakness fundamentally undermines the integrity of credential storage by failing to enforce robust complexity requirements or adequate hashing algorithms that resist brute-force enumeration. In industrial control systems, where continuous operation and secure access are paramount, such a deficiency creates a critical entry point for adversaries seeking unauthorized control over physical processes. The system's reliance on weak cryptographic practices means that even if password hashes are stored securely at rest, their inherent predictability or low entropy makes them susceptible to rapid decryption when exposed.
The operational impact of this flaw is severe, particularly because it facilitates offline password-guessing attacks. An attacker who gains access to the device's storage media or network traffic can extract these hashed credentials without triggering immediate alarms associated with repeated failed login attempts on a live system. Once obtained, the hashes can be processed locally using high-performance computing resources to reverse-engineer the original plaintext passwords. This capability is significantly exacerbated by related vulnerabilities such as CVE-2026-41020, which likely provides the initial vector for hash extraction or further compromises authentication integrity. The combination of weak password policies and accessible hashes allows attackers to recover valid user credentials with high probability, leading to full system compromise.
From a classification perspective, this vulnerability aligns closely with CWE-521, which denotes Weak Password Requirements, as well as CWE-780, referring to Improper Use of Plaintext Credentials in storage or transmission if the hashing method itself is deemed insufficiently strong against modern cracking techniques. Furthermore, the exploitation path maps directly to MITRE ATT&CK technique T1110.003, which covers Brute Force: Password Guessing for Offline Attacks. This categorization highlights that the threat actor does not need to interact with the authentication service in real-time, thereby evading many standard intrusion detection systems that monitor for anomalous login patterns on active sessions.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. Administrators should immediately enforce complex password policies requiring a mix of uppercase and lowercase letters, numbers, and special characters to increase the entropy of stored hashes. Additionally, implementing salting mechanisms with modern hashing algorithms such as Argon2 or bcrypt can significantly raise the computational cost required for offline cracking attempts. Eaton must also consider updating firmware to address any underlying cryptographic weaknesses that allow hash extraction via related vulnerabilities like CVE-2026-41020. Network segmentation and strict access controls should be employed to limit exposure of management interfaces, ensuring that even if credentials are compromised, lateral movement within the industrial network is restricted. Regular audits of authentication configurations against industry standards such as NIST SP 800-63B for digital identity guidelines will help maintain resilience against evolving credential-based threats.