CVE-2025-43892 in FortiOS
Summary
by MITRE • 07/14/2026
A buffer over-read vulnerability in Fortinet FortiOS 7.6.0 through 7.6.2, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions may allow an authenticated remote attacker to return a portion of device memory in the redirect response via submitting a specially crafted request.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical buffer over-read flaw that affects multiple versions of Fortinet FortiOS operating systems including 7.6.0 through 7.6.2, 7.4.0 through 7.4.8, and all versions of 7.2. The issue stems from improper input validation within the web application framework when processing redirect responses, creating a condition where an attacker can manipulate request parameters to trigger memory read operations beyond allocated buffer boundaries. This type of vulnerability falls under CWE-125 which specifically addresses out-of-bounds read conditions in software implementations. The flaw occurs during the handling of HTTP redirect responses where the system fails to properly bounds-check user-supplied data before incorporating it into memory operations, allowing malicious input to reference memory locations outside the intended buffer allocation.
The operational impact of this vulnerability is significant as it enables authenticated remote attackers to potentially extract sensitive information from device memory through carefully crafted requests. When an attacker submits a specially designed HTTP request containing malformed redirect parameters, the vulnerable system returns portions of its internal memory in the response, which could contain confidential data such as session tokens, cryptographic keys, or other sensitive operational information. This memory disclosure capability provides attackers with valuable intelligence that could be leveraged for further exploitation, including credential theft or privilege escalation attacks. The vulnerability operates at the application layer and can be exploited over network connections without requiring physical access to the device.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1213 (Data from Information Repositories) as it enables unauthorized data extraction from system memory. The authenticated nature of the exploit means that attackers must first establish valid credentials or compromise existing user accounts before attempting to leverage this vulnerability, though once authenticated they can potentially access sensitive memory contents. The affected versions span multiple major releases, indicating this is a persistent flaw in Fortinet's implementation that has not been adequately addressed across the product line. Organizations using these vulnerable FortiOS versions face potential exposure to information disclosure attacks that could compromise network security posture and lead to unauthorized access to protected resources.
The recommended mitigation strategies include immediate deployment of Fortinet's security patches and firmware updates that address this specific buffer over-read condition. Network administrators should also implement additional monitoring controls to detect unusual redirect patterns or memory access attempts that might indicate exploitation attempts. Access controls and least privilege principles should be enforced to limit the potential impact if an attacker successfully exploits this vulnerability. Organizations should conduct thorough network assessments to identify all affected devices and ensure proper patch management procedures are in place to prevent similar vulnerabilities from arising in the future. The vulnerability demonstrates the importance of rigorous input validation and memory safety practices in network infrastructure software development, particularly in systems handling authentication and access control functions.