SSH Authentication Vulnerability in MikroTik RouterOS

CVE-2026-67276

What is CVE-2026-67276?

CVE-2026-67276 is a vulnerability identified in MikroTik's RouterOS, which is a widely used operating system for routers developed to facilitate robust networking functionalities. The flaw arises from the SSH authentication mechanism within RouterOS, where the system inadequately verifies the completeness of RSA public keys during authorized user authentication processes. Specifically, while the system checks the key type and modulus, it neglects to verify the exponent component of the key. This oversight allows an attacker equipped with knowledge of a valid RSA modulus to forge a signature by providing an RSA key with an exponent of one. Consequently, this exploit can enable unauthorized access to the SSH command channel under the guise of an authorized user, without the need for the corresponding private key. Such an oversight could lead to severe security breaches within organizations using MikroTik devices, allowing attackers to manipulate network configurations, exfiltrate sensitive data, or potentially disrupt operations.

Potential impact of CVE-2026-67276

1. Unauthorized Access: The primary risk associated with CVE-2026-67276 is the ability for attackers to gain unauthorized SSH access to devices running MikroTik RouterOS. This access allows them to execute commands, alter configurations, and compromise network integrity as if they were legitimate users.

2. Data Breaches: Exploiting this vulnerability can lead to data exfiltration, where attackers can access and steal sensitive organizational information. If exploited, this could result in significant financial and reputational damage, especially for organizations handling confidential data.

3. Network Disruption: Attackers gaining control over network devices can manipulate traffic settings, launch denial-of-service attacks, or reconfigure routing paths, resulting in disrupted services and potential downtime. This disruption can have cascading effects on business operations, leading to loss of service availability and customer trust.

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