CVE-2025-55729 is a critical remote code execution vulnerability affecting the xwiki-pro-macros component of the XWiki platform, specifically in the Remote Macros module designed to facilitate content migration from Confluence. The vulnerability arises from improper encoding or escaping of output (CWE-116) in the handling of the ac:type attribute within the ConfluenceLayoutSection macro and the classes parameter used in XWiki syntax. Versions from 1.0 up to but not including 1.26.5 are affected. The lack of proper escaping allows an attacker with edit permissions on any page to inject malicious XWiki syntax, leading to remote code execution without requiring authentication or user interaction. This vulnerability has a CVSS v3.1 base score of 10.0, indicating critical severity, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and complete impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The vulnerability is fixed in version 1.26.5. No known exploits are currently reported in the wild, but the ease of exploitation and severity make it a significant threat. The vulnerability allows attackers to execute arbitrary code on the server hosting the XWiki instance, potentially leading to full system compromise, data exfiltration, and disruption of services. The root cause is the failure to properly escape user-controllable input in macros that render content, enabling syntax injection attacks that escalate to remote code execution.

For European organizations using XWiki with the vulnerable xwiki-pro-macros versions, this vulnerability poses a severe risk. XWiki is often used in enterprise environments for collaborative documentation and knowledge management, including in sectors such as government, education, and private industry. Exploitation could lead to unauthorized access to sensitive internal documentation, intellectual property theft, and disruption of critical collaboration services. The ability to execute arbitrary code remotely without authentication means attackers can pivot within networks, deploy ransomware, or conduct espionage. Given the collaborative nature of XWiki, many users may have edit permissions, increasing the attack surface. The impact extends beyond confidentiality to integrity and availability, potentially causing widespread operational disruption. European organizations subject to strict data protection regulations (e.g., GDPR) may face compliance and legal consequences if breaches occur due to this vulnerability.

1. Immediate upgrade to xwiki-pro-macros version 1.26.5 or later, where the vulnerability is patched. 2. Restrict edit permissions on XWiki pages to trusted users only, minimizing the number of users who can exploit the vulnerability. 3. Implement web application firewalls (WAFs) with custom rules to detect and block suspicious macro usage or injection patterns related to the ConfluenceLayoutSection macro. 4. Conduct thorough audits of existing XWiki instances to identify and remediate any unauthorized or suspicious content injections. 5. Employ network segmentation and least privilege principles to limit the potential lateral movement if exploitation occurs. 6. Monitor logs and alerts for unusual activity related to XWiki editing and macro usage. 7. Educate administrators and users about the risks of editing macros and the importance of applying security patches promptly.