CVE-2019-25321 in FTP Navigator
Summary
by MITRE • 02/13/2026
FTP Navigator 8.03 contains a stack overflow vulnerability that allows attackers to execute arbitrary code by overwriting Structured Exception Handler (SEH) registers. Attackers can craft a malicious payload that triggers a buffer overflow when pasted into the Custom Command textbox, enabling remote code execution and launching the calculator as proof of concept.
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Analysis
by VulDB Data Team • 03/03/2026
The vulnerability identified as CVE-2019-25321 represents a critical stack overflow flaw within FTP Navigator version 8.03 that fundamentally compromises the application's memory management integrity. This vulnerability exists in the application's handling of user input through the Custom Command textbox functionality, where insufficient bounds checking allows maliciously crafted payloads to overwrite critical memory structures. The flaw specifically targets the Structured Exception Handler mechanism, which serves as a crucial defensive layer in windows operating systems for managing program exceptions and errors. When an attacker successfully exploits this vulnerability, they can manipulate the SEH registers to redirect program execution flow, effectively bypassing standard security measures and gaining unauthorized control over the affected system.
The technical implementation of this vulnerability stems from improper input validation and memory handling within the FTP Navigator application's command processing subsystem. When users paste malicious content into the Custom Command textbox, the application fails to properly validate the input length against available buffer space, creating an exploitable condition where the buffer overflow occurs during string processing operations. This particular implementation follows the classic stack-based buffer overflow pattern that has been documented in numerous security advisories and represents a well-understood attack vector within the cybersecurity community. The vulnerability is particularly dangerous because it allows for arbitrary code execution without requiring elevated privileges, as the application runs with the privileges of the user who initiated the process.
The operational impact of this vulnerability extends beyond simple remote code execution capabilities to encompass complete system compromise potential. Attackers can leverage this flaw to execute malicious payloads that may include malware deployment, privilege escalation attempts, or data exfiltration operations. The proof of concept demonstration using calculator execution illustrates that the vulnerability enables full control over the target system's execution environment, allowing attackers to perform actions such as creating new user accounts, modifying system files, or establishing persistent backdoors. This makes the vulnerability particularly attractive to threat actors seeking to establish long-term access to compromised systems, as the exploit can be reliably reproduced and executed without requiring complex environmental conditions or specialized knowledge beyond basic exploitation techniques.
Organizations should implement immediate mitigations including updating to patched versions of FTP Navigator or applying vendor-provided security updates that address the buffer overflow conditions in the Custom Command processing functionality. Network segmentation and access controls should be enforced to limit exposure of vulnerable systems, while application whitelisting policies can prevent unauthorized execution of malicious payloads. Security monitoring should be enhanced to detect unusual command execution patterns or attempts to manipulate application input fields, with particular attention to monitoring for calculator launches or other proof-of-concept executions. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow and represents a direct threat to the integrity of the application's memory management, making it a critical target for immediate remediation efforts. This flaw also demonstrates characteristics consistent with attack patterns documented in the MITRE ATT&CK framework under the execution and privilege escalation tactics, emphasizing the need for comprehensive defensive measures that address both the immediate vulnerability and broader exploitation vectors.