CVE-2025-68435 is an authentication bypass vulnerability classified under CWE-305 affecting the Zerobyte backup automation tool developed by nicotsx. Versions prior to 0.18.5 and 0.19.0 fail to properly apply authentication middleware to certain API endpoints, resulting in these endpoints being accessible without valid session credentials. This design flaw allows attackers to bypass authentication controls and interact with the API as if they were authorized users. The vulnerability is remotely exploitable over the network without any privileges or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The impact includes unauthorized access to backup data, potentially leading to confidentiality breaches and integrity violations, though availability is not directly affected. Zerobyte is typically used for automating backup processes, so unauthorized access could allow attackers to read, modify, or delete backup configurations and data, severely compromising data protection strategies. The vendor has addressed the issue in versions 0.18.5 and 0.19.0 by properly enforcing authentication middleware on all API endpoints. Until upgrades can be applied, organizations are advised to restrict Zerobyte instances to trusted internal networks using firewall rules or network segmentation to reduce exposure. No public exploits have been reported yet, but the vulnerability’s critical severity and ease of exploitation make it a high priority for patching.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of backup data managed by Zerobyte. Unauthorized access to backup data can lead to data leakage, tampering, or deletion, undermining business continuity and compliance with data protection regulations such as GDPR. Organizations that expose Zerobyte instances beyond their internal networks—such as in hybrid cloud environments or through remote access—are particularly vulnerable. The impact extends to sectors with stringent data protection requirements, including finance, healthcare, and critical infrastructure, where backup integrity is paramount. Exploitation could facilitate further attacks, such as ransomware or data exfiltration, by providing attackers with access to backup repositories. Given the critical CVSS score and the lack of required authentication, the threat is severe and demands immediate remediation to prevent potential breaches and operational disruptions.

1. Upgrade Zerobyte instances immediately to version 0.18.5 or 0.19.0 where the authentication bypass vulnerability is fixed. 2. Until upgrades are possible, implement strict network access controls by restricting Zerobyte API access to trusted internal networks only, using firewall rules and network segmentation. 3. Monitor network traffic to and from Zerobyte instances for unusual or unauthorized API requests that could indicate exploitation attempts. 4. Conduct regular audits of Zerobyte configurations and access logs to detect any unauthorized access or anomalies. 5. Employ intrusion detection/prevention systems (IDS/IPS) to identify and block suspicious activity targeting Zerobyte endpoints. 6. Educate IT and security teams about this vulnerability and ensure patch management processes prioritize this update. 7. If Zerobyte is integrated with other systems, verify that those integrations do not expose the vulnerable API endpoints externally. 8. Consider deploying Web Application Firewalls (WAFs) with rules to block unauthenticated access to Zerobyte API endpoints as an additional layer of defense.