CVE-2026-73442 in EOS
Summary
by MITRE • 09/16/2026
On affected platforms running Arista EOS with VRRP enabled, the peer device VRRP authentication credentials are logged in cleartext on the switch, allowing an authenticated user with sufficient privileges to view agent trace logs (or a system receiving forwarded log output) to obtain the peer device VRRP authentication credentials without having access to the network segment on which VRRP is running.
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Analysis
by VulDB Data Team • 09/17/2026
The vulnerability described involves a critical information disclosure flaw within Arista EOS when Virtual Router Redundancy Protocol, or VRRP, is enabled. This issue stems from the system's logging mechanism inadvertently capturing sensitive authentication data in plaintext rather than masking it or storing it securely. Specifically, the peer device's VRRP authentication credentials are written directly to agent trace logs on the switch. This behavior represents a significant deviation from secure configuration practices where secrets such as passwords and keys should never be persisted in log files that may have broader accessibility than intended administrative interfaces. The presence of these cleartext credentials creates a direct pathway for attackers who might otherwise lack network-level access to compromise high-availability infrastructure components.
From a technical perspective, the flaw allows an authenticated user with sufficient privileges on the switch to view agent trace logs and extract the VRRP authentication credentials. This means that even if an attacker does not have physical or logical access to the specific network segment where VRRP is operating, they can still obtain the necessary secrets by accessing log data stored locally on the device or intercepted from forwarded log output sent to a centralized logging server. The operational impact of this vulnerability is severe because it undermines the integrity and confidentiality guarantees provided by VRRP authentication mechanisms. If an adversary obtains these credentials, they could potentially spoof router advertisements, disrupt failover processes, or perform man-in-the-middle attacks against traffic routed through the virtual gateway, leading to service disruption or data interception for end users relying on that infrastructure.
This vulnerability aligns with CWE-532, which classifies information exposure through log files as a distinct category of security weakness. The improper handling and storage of sensitive authentication materials in logs is a common pitfall in network device software development where debugging features are left enabled or logging verbosity is not properly constrained for production environments. Furthermore, the exploitation scenario maps to MITRE ATT&CK technique T1078, specifically Valid Accounts, as it involves using legitimate credentials with elevated privileges to access sensitive information that should be restricted. The ability to retrieve these secrets without network segment access also relates to lateral movement and privilege escalation vectors where log files serve as a secondary data source for attackers seeking to expand their foothold within the enterprise environment.
Mitigation strategies must focus on immediate remediation of logging configurations alongside long-term architectural improvements. Administrators should immediately review VRRP configuration settings and ensure that authentication is using strong, complex passwords rather than simple text strings if possible, although this does not fully mitigate the log exposure issue. More critically, organizations must adjust syslog or trace logging levels to exclude sensitive data fields from being recorded in plaintext. This may involve disabling verbose agent tracing on production devices or configuring specific filters to mask authentication parameters before they are written to disk or forwarded externally. Additionally, access controls for viewing these logs should be strictly limited to the minimum number of necessary administrators, and log files themselves should be stored with restricted file permissions to prevent unauthorized reading by lower-privileged accounts. Regular audits of log content can help detect if such sensitive data is being inadvertently captured, ensuring that security monitoring tools do not become a source of credential leakage.