Buffer Over-Read in Fortinet FortiOS

Executive Summary

CVE-2025-43892 is a buffer over-read vulnerability in Fortinet FortiOS, FortiProxy, and FortiSASE products. This vulnerability occurs when an authenticated remote attacker submits a specially crafted request, allowing them to read beyond the allocated memory in the authd and wad daemons. As a result, the attacker may retrieve a portion of device memory in the redirect response.

The vulnerability affects specific versions of FortiOS (7.6.0 through 7.6.2, 7.4.0 through 7.4.8, and all 7.2 versions), FortiProxy, and FortiSASE. It is classified under CWE-126 (Buffer Over-read) and has a medium severity rating with a CVSS v3.1 base score of 4.3.

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Detection Guidance

Detecting CVE-2025-43892 on your network or system involves checking for the affected Fortinet product versions and monitoring for suspicious activity related to the authd and wad daemons.

• Verify the installed FortiOS, FortiProxy, or FortiSASE versions. The vulnerability affects FortiOS 7.6.0 through 7.6.2, 7.4.0 through 7.4.8, and all versions of 7.2; FortiProxy 7.6, 7.4, and 7.2; and FortiSASE.
• Check Fortinet device logs for unusual redirect responses or memory-related errors in the authd and wad daemons. Look for signs of memory corruption or unexpected data in responses.
• Use Fortinet's official tools or security advisories to scan for vulnerable configurations. Fortinet may provide specific detection scripts or signatures for this CVE.

No specific commands are provided in the context, but you can use standard Fortinet CLI commands to check the version and logs. For example:

• To check the FortiOS version: execute 'get system status' or 'show full-configuration system global' in the CLI.
• To review logs for suspicious activity: execute 'execute log display' or filter logs for authd/wad-related entries.

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Impact Analysis

If you are using an affected version of Fortinet FortiOS, FortiProxy, or FortiSASE, this vulnerability could impact you in the following ways:

• An authenticated attacker could exploit this vulnerability to access sensitive information stored in device memory, such as credentials, session tokens, or other confidential data.
• The attacker could use the leaked memory contents to escalate privileges, move laterally within your network, or launch further attacks.
• Exposure of internal system details could aid attackers in crafting more targeted exploits against your infrastructure.

Since the vulnerability requires authentication, the risk is primarily from insiders or attackers who have already compromised valid credentials.

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Compliance Impact

This vulnerability may impact compliance with several common standards and regulations, depending on the data exposed and the context of your organization:

• GDPR (General Data Protection Regulation): If the leaked memory contains personal data of EU citizens, this could constitute a data breach under GDPR. Organizations may face fines, mandatory breach notifications, and reputational damage if they fail to mitigate the vulnerability or report incidents promptly.
• HIPAA (Health Insurance Portability and Accountability Act): If the affected system processes or stores protected health information (PHI), exploitation of this vulnerability could lead to unauthorized access to PHI, resulting in HIPAA violations. Covered entities may be required to report the breach and could face penalties.
• PCI DSS (Payment Card Industry Data Security Standard): If the device memory contains payment card data, this vulnerability could lead to non-compliance with PCI DSS requirements for protecting cardholder data. Organizations may face fines or restrictions on processing payments.
• Other industry-specific regulations: Depending on the nature of the data exposed, this vulnerability could also impact compliance with frameworks like SOX (Sarbanes-Oxley Act), FISMA (Federal Information Security Management Act), or sector-specific guidelines.

To maintain compliance, organizations should apply the available patches or mitigations provided by Fortinet and conduct a risk assessment to determine if any sensitive data was exposed.

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Mitigation Strategies

To mitigate CVE-2025-43892, follow these immediate steps:

• Upgrade to the latest patched version of FortiOS, FortiProxy, or FortiSASE as recommended by Fortinet. The advisory published on July 14, 2026, likely includes fixed versions.
• If upgrading is not immediately possible, apply any available workarounds or mitigations provided by Fortinet in their advisory. This may include disabling specific features or restricting access to vulnerable daemons.
• Ensure that only authenticated and trusted users have access to the affected systems. Restrict network access to the management interfaces of Fortinet devices.
• Monitor network traffic and logs for signs of exploitation attempts, such as unusual redirect responses or memory-related errors.
• Refer to Fortinet's PSIRT advisory for detailed mitigation steps and updates: https://fortiguard.fortinet.com/psirt.

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