CVE-2026-59840 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, FortiProxy 7.6.0 through 7.6.5, FortiProxy 7.4.0 through 7.4.13, FortiProxy 7.2 all versions may allow attacker to information disclosure via <insert attack vector here>
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical buffer over-read condition affecting multiple Fortinet security products including FortiOS and FortiProxy across several version ranges. The flaw occurs when the software processes certain input data without proper bounds checking, allowing an attacker to read memory locations beyond the allocated buffer boundaries. Such vulnerabilities typically arise from insufficient validation of input parameters or improper handling of data structures during processing operations.
The technical implementation of this vulnerability stems from inadequate memory management practices within the affected software components. When legitimate input reaches the system, it triggers a scenario where the application attempts to access memory regions that extend beyond the intended buffer limits. This over-read behavior can potentially expose sensitive information stored in adjacent memory locations including authentication credentials, session tokens, cryptographic keys, or other confidential data structures. The vulnerability is particularly concerning because it operates at the kernel or core processing level where such memory access issues can provide attackers with extensive system intelligence.
From an operational perspective, this information disclosure vulnerability poses significant risks to organizations relying on Fortinet security infrastructure. Attackers could leverage this weakness to extract sensitive configuration data, user credentials, or system internals that would otherwise remain protected. The impact extends beyond simple data exposure as the leaked information could enable more sophisticated attacks including privilege escalation, lateral movement within networks, or targeted exploitation of other system components. Network administrators face potential compromise of their entire security posture if this vulnerability remains unpatched.
The vulnerability aligns with CWE-125 which specifically addresses out-of-bounds read conditions in software implementations. From an adversarial perspective, this weakness maps to multiple ATT&CK techniques including credential access through information discovery and privilege escalation via system information discovery. Organizations should prioritize immediate remediation by applying the latest security patches provided by Fortinet as these vulnerabilities are actively being exploited in the wild.
Mitigation strategies include implementing network segmentation to limit potential attack vectors, deploying intrusion detection systems to monitor for exploitation attempts, and conducting comprehensive vulnerability assessments of all affected Fortinet products across the enterprise. Regular security audits should verify proper patch management procedures and ensure that all system components maintain current security updates. Additionally, organizations should consider implementing extended monitoring for unusual memory access patterns or data exfiltration attempts that might indicate exploitation of this vulnerability.
The broader implications extend to compliance requirements where such information disclosure vulnerabilities could result in regulatory violations under standards like pci dss, hipaa, or gdpr depending on the nature of data processed by affected systems. Organizations must also evaluate their incident response capabilities to ensure rapid detection and remediation of potential exploitation attempts. Regular security awareness training for system administrators should emphasize the importance of timely patch deployment and monitoring for emerging threats targeting Fortinet products.