CVE-2025-13810 identifies a path traversal vulnerability in the jsnjfz WebStack-Guns 1.0 product, specifically within the renderPicture function located in src/main/java/com/jsnjfz/manage/modular/system/controller/KaptchaController.java. Path traversal vulnerabilities occur when an application fails to properly sanitize user-supplied input that is used to construct file paths, allowing attackers to manipulate the path to access files outside the intended directory. In this case, remote attackers can craft malicious requests to the renderPicture function to traverse directories and access arbitrary files on the server filesystem. The vulnerability is remotely exploitable without requiring authentication, user interaction, or privileges, increasing its risk profile. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P) indicates network attack vector, low attack complexity, no privileges or user interaction needed, and partial confidentiality impact due to potential unauthorized file access. Although no confirmed exploits in the wild exist, public proof-of-concept code has been released, raising the risk of exploitation. The vendor was notified early but has not provided any response or patch, leaving users exposed. This vulnerability could lead to unauthorized disclosure of sensitive files, configuration data, or system information, potentially aiding further attacks or data breaches. The lack of vendor response and patch availability necessitates immediate mitigation efforts by users.

For European organizations, this vulnerability poses a significant risk of unauthorized data exposure and information leakage. Attackers exploiting the path traversal flaw could access sensitive files such as configuration files, credentials, or proprietary data stored on affected servers. This could lead to further compromise, including privilege escalation or lateral movement within networks. Organizations in sectors with stringent data protection requirements, such as finance, healthcare, and government, face increased regulatory and reputational risks if sensitive data is exposed. The medium severity rating reflects the moderate impact on confidentiality without direct integrity or availability effects; however, the ease of exploitation and lack of authentication requirements amplify the threat. The absence of vendor patches means organizations must rely on internal controls and mitigations to reduce exposure. Additionally, the public availability of exploit code increases the likelihood of opportunistic attacks targeting vulnerable systems across Europe.

Given the absence of vendor patches, European organizations should implement immediate compensating controls. First, conduct a thorough code review of the renderPicture function and related file handling logic to identify and remediate improper input validation. Implement strict input sanitization to disallow directory traversal characters (e.g., ../) and enforce whitelist-based file path validation. Employ sandboxing or chroot environments to limit file system access scope for the affected application components. Restrict network access to the vulnerable service using firewalls or network segmentation to reduce exposure to untrusted sources. Monitor logs for suspicious requests attempting path traversal patterns. If feasible, replace or upgrade the WebStack-Guns software to a more secure alternative or a patched version once available. Additionally, conduct regular security assessments and penetration testing focused on file path manipulation vulnerabilities. Finally, maintain an incident response plan to quickly address any exploitation attempts.