CVE-2025-13810 identifies a path traversal vulnerability in the jsnjfz WebStack-Guns 1.0 software, 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 improperly sanitizes user-supplied input used to construct file paths, allowing attackers to traverse directories and access files outside the intended scope. In this case, the vulnerability enables remote attackers to manipulate the file path parameter without authentication or user interaction, potentially reading arbitrary files on the server. This can lead to exposure of sensitive information such as configuration files, credentials, or source code. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and low impact on confidentiality (VC:L) with no impact on integrity or availability. The exploit has been publicly disclosed, increasing the risk of exploitation, but no active exploitation has been reported yet. The vendor was notified early but has not issued any response or patch, leaving users exposed. The lack of patches necessitates immediate mitigation efforts by users. The vulnerability’s presence in a web controller handling image rendering suggests that the attack surface is exposed via web requests, increasing the risk for internet-facing deployments. Without proper input validation and path normalization, the system is vulnerable to directory traversal attacks that can compromise confidentiality and potentially facilitate further attacks.

For European organizations using jsnjfz WebStack-Guns 1.0, this vulnerability poses a significant risk of unauthorized disclosure of sensitive files hosted on affected servers. Attackers exploiting this flaw can access configuration files, credentials, or other critical data, potentially leading to further compromise such as privilege escalation or lateral movement within networks. The vulnerability’s remote and unauthenticated nature increases the likelihood of exploitation, especially for internet-facing systems. Confidentiality is primarily impacted, but the exposure of sensitive data can indirectly affect integrity and availability if attackers leverage the information to deploy ransomware or disrupt services. Organizations in sectors with high regulatory requirements for data protection (e.g., finance, healthcare, government) face increased compliance risks and potential legal consequences if breaches occur. The absence of vendor patches means organizations must rely on internal mitigations and monitoring to reduce risk. Additionally, the public availability of exploit code lowers the barrier for attackers, increasing the threat landscape. The medium severity rating reflects the moderate but tangible risk, emphasizing the need for timely action to prevent data breaches and maintain operational security.

1. Immediate code audit and remediation: Review the renderPicture function and all file path handling code to implement strict input validation, ensuring that user-supplied parameters cannot include directory traversal sequences such as '../'. 2. Implement path normalization and canonicalization techniques to resolve and validate file paths before accessing the filesystem. 3. Employ allowlisting of permissible file paths or directories to restrict file access strictly to intended resources. 4. Deploy Web Application Firewalls (WAFs) with rules to detect and block path traversal attack patterns targeting the affected endpoints. 5. Restrict network exposure of WebStack-Guns instances by limiting access to trusted IP ranges or internal networks where possible. 6. Monitor logs for suspicious requests containing traversal payloads or unusual file access patterns. 7. Prepare incident response plans to quickly address potential exploitation attempts. 8. Engage with the vendor or community to seek patches or updates; if unavailable, consider alternative software solutions or compensating controls. 9. Conduct regular security assessments and penetration testing focusing on file handling vulnerabilities. 10. Educate development teams on secure coding practices related to file system access.