Out-of-Bounds Read in Fortinet FortiAuthenticator

Executive Summary

CVE-2025-53379 is an out-of-bounds read vulnerability affecting Fortinet FortiAuthenticator versions 6.6.0 through 6.6.2 and all versions of 6.5. This flaw allows a remote unauthenticated attacker to send a specially crafted request to the affected system.

An out-of-bounds read occurs when the software reads data beyond the intended boundary of a buffer or memory location. In this case, the vulnerability could enable the attacker to retrieve sensitive information from the system.

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Detection Guidance

The provided context does not include specific detection methods or commands for identifying CVE-2025-53379 on a network or system. Detection typically involves checking for vulnerable versions of Fortinet FortiAuthenticator (6.6.0 through 6.6.2 or any 6.5 version) and monitoring network traffic for suspicious requests targeting the affected component.

To detect vulnerable versions, you may use the following general approaches:

• Check the installed version of FortiAuthenticator via its administrative interface or command-line tools. Compare it against the affected versions listed in the CVE description.
• Use network scanning tools to identify FortiAuthenticator instances and their versions. Tools like Nmap with version detection scripts may help.
• Monitor network traffic for unusual or malformed requests to the FortiAuthenticator service, particularly those that could trigger the out-of-bounds read vulnerability.

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Impact Analysis

If you are using a vulnerable version of Fortinet FortiAuthenticator, this vulnerability could have the following impacts:

• Exposure of sensitive information: A remote attacker could exploit this flaw to access confidential data stored or processed by the FortiAuthenticator.
• Unauthorized access: The retrieved sensitive information could be used to facilitate further attacks, such as credential theft or unauthorized access to other systems.
• Compromise of authentication processes: Since FortiAuthenticator is used for authentication, the vulnerability could undermine the security of authentication mechanisms in your environment.

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Compliance Impact

This vulnerability could impact compliance with several standards and regulations, depending on the nature of the sensitive information exposed:

• GDPR (General Data Protection Regulation): If the exposed information includes personal data of EU citizens, this could constitute a data breach under GDPR. Organizations may face fines, mandatory breach notifications, and reputational damage.
• HIPAA (Health Insurance Portability and Accountability Act): If the FortiAuthenticator is used in a healthcare environment and the exposed data includes protected health information (PHI), this could violate HIPAA's security and privacy rules, leading to penalties and corrective action plans.
• Other standards: Depending on the industry, this vulnerability could also affect compliance with standards like PCI DSS (if payment data is exposed) or sector-specific regulations that mandate the protection of sensitive information.

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Mitigation Strategies

Based on the provided context, here are the immediate steps to mitigate CVE-2025-53379:

• Upgrade Fortinet FortiAuthenticator to a version that is not affected by this vulnerability. The context does not specify a patched version, so refer to Fortinet's official advisories or release notes for the latest fixed version.
• If upgrading is not immediately possible, restrict network access to the FortiAuthenticator device to trusted sources only. Use firewalls or network segmentation to limit exposure to remote unauthenticated attackers.
• Monitor the device for any signs of exploitation, such as unusual network traffic or unauthorized access attempts.
• Review Fortinet's security advisories for additional mitigation steps or workarounds specific to this vulnerability.

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