CVE-2019-25714 in A8-V5 Collaborative Management Software
Summary
by MITRE • 04/21/2026
Seeyon OA A8 contains an unauthenticated arbitrary file write vulnerability in the /seeyon/htmlofficeservlet endpoint that allows remote attackers to write arbitrary files to the web application root by sending specially crafted POST requests with custom base64-encoded payloads. Attackers can write JSP webshells to the web root and execute them through the web server to achieve arbitrary OS command execution with web server privileges. Exploitation evidence was first observed by the Shadowserver Foundation on 2021-03-26 (UTC).
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Analysis
by VulDB Data Team • 05/23/2026
The vulnerability resides within the Seeyon OA A8 web application where the /seeyon/htmlofficeservlet endpoint fails to properly validate incoming requests, creating an unauthenticated arbitrary file write condition that can be exploited by remote attackers without requiring any prior authentication credentials. This flaw represents a critical security weakness that directly violates the principle of least privilege and proper input validation as defined by CWE-22, which addresses path traversal vulnerabilities that allow unauthorized file operations. The vulnerability manifests when the application processes specially crafted POST requests containing base64-encoded payloads that bypass normal security controls, enabling attackers to write files directly to the web application root directory.
The technical exploitation mechanism leverages the application's failure to sanitize user-supplied data during the file upload process, allowing attackers to inject malicious content through the HTTP POST method. The base64-encoded payloads are decoded and written to the server filesystem, where attackers can place JSP webshells that execute within the context of the web server process. This arbitrary file write capability directly maps to CWE-434 which describes insecure file upload vulnerabilities where applications accept files without proper validation, and the resulting security implications include complete compromise of the web server's functionality and potential lateral movement within the network infrastructure. The vulnerability operates at the application layer and can be exploited from external network positions without requiring any credentials or prior access to the system.
The operational impact of this vulnerability is severe as it provides attackers with persistent access to the target system through the web server privileges, enabling them to execute arbitrary operating system commands and establish backdoors for continued access. The webshell execution capability allows for remote code execution with the privileges of the web server process, which typically runs with limited system privileges but can still provide attackers with significant control over the affected server. Attackers can leverage this vulnerability for data exfiltration, system reconnaissance, and potentially escalate privileges to gain administrative access to the underlying operating system. This vulnerability directly aligns with ATT&CK technique T1505.003 for server-side web shell execution and T1059.007 for command and script interpreter execution through web shells.
The first evidence of exploitation was documented by the Shadowserver Foundation on 2021-03-26, indicating that this vulnerability had been actively weaponized in the wild for at least several months prior to public disclosure. This timeframe suggests that the vulnerability was likely exploited by threat actors for reconnaissance and initial compromise activities, potentially as part of broader attack campaigns targeting enterprise networks. The exploitation pattern demonstrates the effectiveness of this vulnerability in bypassing standard security controls and highlights the importance of proper input validation and authentication mechanisms in web applications. Organizations should implement immediate mitigations including network segmentation, web application firewall rules blocking access to the vulnerable endpoint, and disabling unnecessary file upload functionality to prevent exploitation. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other applications and systems within the organization's infrastructure.