CVE-2026-22316 in FL SWITCH 2005
Summary
by MITRE • 03/18/2026
A remote attacker with user privileges for the webUI can use the setting of the TFTP Filename with a POST Request to trigger a stack-based Buffer Overflow, resulting in a DoS attack.
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Analysis
by VulDB Data Team • 03/22/2026
This vulnerability resides within a web-based user interface that manages TFTP (Trivial File Transfer Protocol) functionality, presenting a significant security risk for systems relying on this service. The flaw manifests when a remote attacker with legitimate user privileges manipulates the TFTP filename parameter through a POST request to the web interface. The vulnerability is classified as a stack-based buffer overflow, which occurs when the application fails to properly validate or limit the length of user-supplied input before copying it into a fixed-size buffer located on the stack. This specific implementation flaw allows an attacker to exceed the allocated buffer space, potentially overwriting adjacent memory locations including return addresses and control data. The attack vector is particularly concerning because it requires only user-level privileges to execute, meaning that any authenticated user could potentially exploit this weakness. The resulting denial of service condition can render the affected web interface completely inaccessible to legitimate users, effectively disabling critical file transfer capabilities and potentially disrupting broader network operations that depend on the TFTP service.
The technical exploitation of this vulnerability follows established patterns found in CWE-121 stack-based buffer overflow conditions, where insufficient bounds checking allows attackers to overwrite program execution flow. According to ATT&CK framework, this represents a privilege escalation and denial of service technique that can be categorized under T1499.004 (Unauthorizied Access) and T1499 (Network Denial of Service). The buffer overflow occurs during the processing of the TFTP filename parameter, where the application likely uses a fixed-length character array or buffer to store the filename without proper input validation. When the attacker supplies a filename exceeding the buffer capacity, the excess data overflows into adjacent stack memory, potentially corrupting the program state and causing unpredictable behavior or complete application crash. This vulnerability demonstrates poor input validation practices and inadequate memory management within the web application's TFTP configuration handling module.
The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise the integrity of the entire system's file transfer operations and potentially provide a foothold for further attacks. When the DoS condition occurs, legitimate users lose access to critical file transfer capabilities that may be essential for system administration, firmware updates, or network configuration management. The vulnerability's accessibility to authenticated users means that insider threats or compromised accounts could leverage this weakness for malicious purposes. Organizations relying on TFTP services through this web interface may experience extended downtime while administrators investigate and remediate the issue, potentially affecting multiple users and systems that depend on these file transfer operations. The attack can be executed remotely without requiring special tools or elevated privileges beyond basic user authentication, making it particularly dangerous in environments where user access controls may not be strictly enforced.
Mitigation strategies should focus on implementing robust input validation and bounds checking mechanisms within the web application's TFTP configuration handling code. The primary defense involves limiting the maximum length of TFTP filename parameters and implementing proper buffer management techniques that prevent stack overflows. Organizations should deploy input sanitization measures that validate all user-supplied data before processing, ensuring that filenames conform to expected formats and length restrictions. Network segmentation and access control measures can help limit the scope of potential exploitation by restricting user access to only necessary functionality. Regular security updates and patches should be applied immediately to address the vulnerability, while monitoring systems should be configured to detect unusual POST request patterns targeting the TFTP configuration endpoints. Additionally, implementing application-level firewalls or web application firewalls can provide an additional layer of protection by filtering malicious requests before they reach the vulnerable application components. The vulnerability also highlights the importance of following secure coding practices and conducting regular code reviews to identify similar buffer overflow conditions that could exist in other parts of the application.