CVE-2026-73466 in EOS
Summary
by MITRE • 09/15/2026
On affected platforms running Arista EOS, under certain circumstances user passwordss may be written in clear text to log files during operations when specialized non-standard debugging trace levels are explicitly enabled.
To exploit these vulnerabilities, a malicious actor must already possess authenticated local administrative access to the device shell, and specialized non-standard debugging trace levels must be explicitly enabled.
This issue was discovered internally by Arista, and the company is not aware of any malicious exploitation of this vulnerability in customer networks.
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Analysis
by VulDB Data Team • 09/15/2026
The identified security flaw within Arista EOS represents a critical configuration-dependent information disclosure vulnerability where sensitive authentication credentials are inadvertently persisted to system log files in plaintext format. This issue arises specifically when specialized non-standard debugging trace levels are explicitly enabled by an administrator for diagnostic purposes. Under these specific operational conditions, the operating system fails to sanitize or mask password fields during logging operations, resulting in the direct exposure of user passwords within plain text logs that may be accessible through standard log viewing mechanisms or centralized logging systems. This behavior violates fundamental security principles regarding the handling of sensitive data and creates a significant risk vector for credential theft if proper access controls are not strictly enforced on log storage locations.
From a technical perspective, this vulnerability is classified under CWE-532, which covers Information Exposure Through Log Files. The root cause lies in the logging subsystem's failure to apply appropriate obfuscation or masking techniques when processing authentication-related events during high-level debugging sessions. While standard operational modes typically handle credentials securely by either omitting them from logs or replacing them with masked characters such as asterisks, the activation of non-standard debug traces bypasses these safeguards. This allows any process or user with read access to the relevant log directories to view the actual plaintext passwords associated with administrative accounts on the device shell. The vulnerability is not triggered during normal operation but requires a specific combination of authenticated local administrative access and the deliberate enablement of verbose debugging features, indicating that it is primarily an operational risk rather than a remote exploitation vector.
The operational impact of this flaw centers on the potential compromise of network infrastructure security through credential harvesting. Although Arista has noted no known malicious exploitation in customer networks to date, the existence of plaintext passwords in log files poses a severe threat if those logs are accessed by unauthorized parties or retained indefinitely without proper protection. An attacker with local administrative access could leverage this vulnerability to extract credentials for other systems that may share password policies or reuse accounts across different network devices. This facilitates lateral movement within the enterprise environment and undermines the integrity of identity-based security controls. Furthermore, compliance frameworks such as PCI DSS and HIPAA require strict control over sensitive data in logs, making this behavior a potential violation of regulatory requirements even if no active exploitation occurs.
To mitigate this risk, administrators should adhere to the principle of least privilege by restricting access to log files only to essential personnel who have an explicit business need for such information. It is critical to disable specialized non-standard debugging trace levels immediately after troubleshooting activities are completed, as these modes are intended for temporary diagnostic use and not for sustained operation. Additionally, organizations should implement robust log management practices that include encryption of logs at rest and in transit, along with strict access control lists on log storage directories. Regular audits of logging configurations can help ensure that verbose debugging is not left enabled inadvertently. By treating debug-enabled states as high-risk operational modes requiring heightened security controls, network operators can significantly reduce the likelihood of credential exposure through this vector.