CVE-2019-25466 in Easy File Sharing Web Server
Summary
by MITRE • 03/11/2026
Easy File Sharing Web Server 7.2 contains a local structured exception handling buffer overflow vulnerability that allows local attackers to execute arbitrary code by creating a malicious username. Attackers can craft a username with a payload containing 4059 bytes of padding followed by a nseh value and seh pointer to trigger the overflow when adding a new user account.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 03/14/2026
The vulnerability identified as CVE-2019-25466 affects Easy File Sharing Web Server version 7.2, representing a critical local privilege escalation flaw that demonstrates the dangers of improper buffer management in server-side applications. This vulnerability exists within the user account creation functionality where the application fails to properly validate the length of username inputs, creating an exploitable condition that can be leveraged by local attackers to gain elevated system privileges. The flaw specifically manifests during the process of adding new user accounts, where the application's structured exception handling mechanism becomes compromised through buffer overflow conditions.
The technical implementation of this vulnerability follows a classic stack-based buffer overflow pattern that aligns with CWE-121, which describes conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The exploit requires attackers to construct a malicious username string that consists of precisely 4059 bytes of padding followed by a valid nseh (next exception handler) value and seh (structured exception handler) pointer. This specific payload construction technique enables the attacker to overwrite the exception handling stack frame and redirect execution flow to malicious code. The vulnerability's exploitation relies on the application's failure to implement proper input validation and bounds checking during username processing, allowing the attacker to manipulate the program's execution flow through controlled memory corruption.
From an operational perspective, this vulnerability presents a significant risk to systems running Easy File Sharing Web Server 7.2, as it allows local attackers to execute arbitrary code with the privileges of the affected service account. The attack vector is particularly concerning because it requires only local system access to exploit, meaning that any user with access to the system can potentially leverage this vulnerability to escalate privileges and gain unauthorized control over the server. The impact extends beyond simple code execution to include potential data theft, system compromise, and lateral movement within network environments where the vulnerable server operates. The vulnerability's exploitation directly maps to ATT&CK technique T1068, which describes the use of local privilege escalation to gain elevated privileges, and T1059, which encompasses the execution of malicious code through various system interfaces.
The mitigation strategies for this vulnerability should include immediate application of vendor patches or updates that address the buffer overflow condition in the user account creation module. System administrators should implement strict input validation controls that enforce maximum length limits on username fields and implement proper bounds checking mechanisms. Additionally, the principle of least privilege should be enforced by running the web server with minimal required permissions and by implementing application sandboxing techniques to limit the potential impact of successful exploitation attempts. Network segmentation and monitoring solutions should be deployed to detect anomalous user account creation activities that might indicate exploitation attempts. Organizations should also conduct comprehensive vulnerability assessments to identify other applications running on affected systems that may share similar buffer handling flaws, as this vulnerability type represents a common class of software security weaknesses that can be exploited across various platforms and applications.