Heap-Based Buffer Overflow in FortiAnalyzer Cloud oftpd Daemon Allows Remote Code Execution
Fortinet disclosed a heap-based buffer overflow in the oftpd daemon of FortiAnalyzer Cloud that could allow remote unauthenticated attackers to execute arbitrary code, though exploitation requires significant effort.
Fortinet has disclosed a heap-based buffer overflow vulnerability (CWE-122) in the oftpd daemon of FortiAnalyzer Cloud, tracked as FG-IR-26-121. The flaw, which carries a CVSSv3 score of 7.3, could allow a remote unauthenticated attacker to execute arbitrary code or commands by sending specifically crafted requests to the affected service. However, successful exploitation would require a large amount of preparation due to Address Space Layout Randomization (ASLR) and network segmentation controls.
The vulnerability affects FortiAnalyzer Cloud versions 7.6.2 through 7.6.4, as well as FortiManager Cloud versions 7.6.2 through 7.6.4. Fortinet has released patches in the form of upgrades to version 7.6.5 or above for both products. The company credited Gwendal Guégniaud of the Fortinet Product Security team for internally discovering and reporting the issue.
According to the advisory, the heap-based buffer overflow exists in the oftpd daemon, which is a component of the FortiAnalyzer Cloud platform. Heap-based buffer overflows occur when a program writes more data to a heap-allocated memory buffer than it can hold, potentially overwriting adjacent memory and allowing an attacker to inject malicious code. In this case, the vulnerability can be triggered without authentication, making it particularly dangerous if reachable.
Fortinet emphasized that thanks to network segmentation, this vulnerability could only be exploited if the attacker already has access to another cloud component belonging to the same entity. This mitigation significantly raises the bar for exploitation, as an attacker would need to first compromise another part of the FortiAnalyzer Cloud infrastructure before being able to target the oftpd daemon.
The CVSSv3 score of 7.3 places this vulnerability in the "high" severity range, though the attack complexity is rated as high due to the ASLR requirement. The vulnerability does not require any user interaction and can be exploited over the network, but the network segmentation requirement limits the attack vector to adjacent networks in practice.
This disclosure follows a pattern of Fortinet addressing security issues in its cloud products. The company has not reported any active exploitation of this vulnerability in the wild, and the advisory was published on April 14, 2026. Fortinet recommends that all customers upgrade to the patched versions as soon as possible to protect their environments.
The vulnerability highlights the ongoing challenge of securing cloud-based management platforms, which often expose multiple services to potential attackers. While the exploitation difficulty is high, the potential impact of arbitrary code execution on a cloud management platform could be severe, potentially allowing an attacker to pivot to other systems or exfiltrate sensitive data.