CVE-2025-13816 is a path traversal vulnerability identified in the moxi159753 Mogu Blog v2 software, specifically affecting versions 5.0 through 5.2. The flaw resides in the FileOperation.unzip function within the ZIP File Handler component, located at /networkDisk/unzipFile. An attacker can exploit this vulnerability by manipulating the fileUrl argument passed to the unzip function, enabling traversal outside the intended directory structure. This can lead to unauthorized access to arbitrary files on the server, potentially exposing sensitive data or enabling further exploitation. The vulnerability can be triggered remotely without requiring user interaction, though it does require low-level privileges (PR:L). The vendor was notified but has not issued a patch or response, and the exploit details have been publicly disclosed, increasing the risk of exploitation. The CVSS 4.0 base score is 5.3, indicating a medium severity with network attack vector, low complexity, no authentication needed, and limited impact on confidentiality, integrity, and availability. No known exploits are currently observed in the wild, but the public disclosure and lack of vendor mitigation increase the urgency for defensive measures.

For European organizations, this vulnerability poses a moderate risk primarily to confidentiality and integrity of data hosted on affected Mogu Blog v2 installations. Attackers exploiting the path traversal could access sensitive files, including configuration files, user data, or credentials stored on the server. This could lead to data breaches or facilitate further attacks such as privilege escalation or remote code execution if combined with other vulnerabilities. The availability impact is limited but could occur if critical files are overwritten or deleted. Organizations running Mogu Blog v2 on public-facing infrastructure are at higher risk, especially if the server is accessible over the internet without adequate network segmentation or access controls. The lack of vendor patching increases the window of exposure, making proactive mitigation essential. The impact is more significant for entities relying on Mogu Blog for critical communications or data storage, including SMEs and public sector bodies in Europe.

Given the absence of an official patch, European organizations should implement several specific mitigations: 1) Immediately restrict access to the /networkDisk/unzipFile endpoint via network controls such as firewalls or web application firewalls (WAFs) to limit exposure to trusted IPs or internal networks only. 2) Employ strict input validation and sanitization on the fileUrl parameter to prevent directory traversal characters (e.g., ../) from being processed. 3) Monitor logs for suspicious requests targeting the unzip functionality and unusual file access patterns. 4) Isolate the Mogu Blog application in a sandboxed environment with minimal privileges and segregated file system permissions to limit the impact of any successful exploitation. 5) Consider disabling or replacing the vulnerable unzip feature if feasible until a vendor patch is available. 6) Maintain regular backups of critical data to enable recovery in case of compromise. 7) Stay alert for any vendor updates or community patches and apply them promptly. 8) Conduct security awareness training for administrators managing Mogu Blog instances to recognize exploitation attempts.