CVE-2018-16277 in XWiki
Summary
by MITRE
The Image Import function in XWiki through 10.7 has XSS.
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Analysis
by VulDB Data Team • 04/29/2026
The vulnerability identified as CVE-2018-16277 represents a cross-site scripting flaw within the Image Import functionality of XWiki versions up to 10.7. This issue arises from insufficient input validation and output encoding mechanisms when processing image import operations, creating an avenue for malicious actors to inject arbitrary JavaScript code into the application's response. The vulnerability specifically affects the image import feature which allows users to import images from external sources or local files, making it a critical concern for web applications that rely on user-uploaded content or external media integration.
The technical exploitation of this vulnerability occurs when an attacker uploads or imports an image with malicious content embedded within its metadata or file structure. The flaw stems from inadequate sanitization of user-supplied data during the image processing pipeline, particularly in how the application handles image attributes, file names, or metadata fields. When the system displays or processes these imported images, the malicious script code gets executed within the context of other users' browsers, potentially leading to session hijacking, data theft, or further exploitation of the compromised environment. This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting vulnerabilities arising from improper output encoding and insufficient input validation.
The operational impact of CVE-2018-16277 extends beyond simple script execution as it can enable attackers to perform various malicious activities including but not limited to stealing user sessions, defacing web pages, redirecting users to malicious sites, or establishing persistent backdoors within the application. The vulnerability is particularly dangerous in collaborative environments where multiple users interact with the platform, as a single compromised image import can affect all users who view or interact with the imported content. The attack surface is broadened by the fact that image import functionality is commonly used in content management systems, wikis, and collaborative platforms where users frequently upload media files.
Organizations utilizing XWiki versions prior to 10.8 should immediately implement mitigation strategies including upgrading to the patched version that addresses this vulnerability through proper input validation and output encoding mechanisms. Additional protective measures include implementing Content Security Policy headers, sanitizing all user-supplied content, and conducting regular security assessments of file upload functionalities. The remediation process should also involve comprehensive code reviews focusing on input validation patterns, output encoding practices, and the handling of external media content. Security teams should monitor for potential exploitation attempts and implement network-based intrusion detection systems to identify suspicious image import activities that may indicate attempted exploitation of this vulnerability. This vulnerability demonstrates the critical importance of proper input validation in web applications and aligns with ATT&CK technique T1203 which covers exploitation of web application vulnerabilities for privilege escalation and persistent access.