CVE-2018-9206 in Siebel CRM
Summary
by MITRE
Unauthenticated arbitrary file upload vulnerability in Blueimp jQuery-File-Upload <= v9.22.0
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Analysis
by VulDB Data Team • 08/13/2026
The CVE-2018-9206 vulnerability represents a critical security flaw in the Blueimp jQuery-File-Upload library version 9.22.0 and earlier, which has been widely adopted across web applications for handling file uploads. This vulnerability stems from insufficient validation mechanisms within the file upload functionality, allowing attackers to bypass authentication requirements and upload arbitrary files to the target system. The flaw specifically affects web applications that implement the jQuery-File-Upload plugin without proper access controls or file type restrictions, creating a significant attack surface that can be exploited by malicious actors.
The technical implementation of this vulnerability resides in the library's handling of file upload requests where authentication checks are either absent or improperly enforced. Attackers can leverage this weakness by sending crafted HTTP requests directly to the upload endpoint without requiring valid credentials, enabling them to upload malicious files such as web shells, scripts, or other harmful content. The vulnerability operates at the application layer and can be classified under CWE-434, which specifically addresses the insecure upload of executable files. This weakness allows for potential remote code execution and privilege escalation within the affected systems, as the uploaded files can be executed with the privileges of the web server process.
The operational impact of CVE-2018-9206 extends beyond simple unauthorized file uploads, as it can lead to complete system compromise and data breaches. When exploited successfully, attackers can gain persistent access to the affected web applications and potentially move laterally within the network infrastructure. The vulnerability affects organizations using vulnerable versions of the jQuery-File-Upload library across various web platforms, including content management systems, file sharing applications, and custom web applications. This weakness aligns with ATT&CK technique T1190, which covers the exploitation of vulnerabilities in web applications to gain initial access and establish persistence within target environments.
Organizations affected by this vulnerability should prioritize immediate remediation through patching to version 9.23.0 or later, which includes proper authentication checks and enhanced file validation mechanisms. Additional mitigations include implementing proper input validation, restricting file types allowed for upload, enforcing strict file name sanitization, and implementing web application firewalls to monitor and block suspicious upload requests. Security teams should also conduct comprehensive vulnerability assessments to identify all instances of the vulnerable library across their infrastructure and ensure proper access controls are implemented at the application level. The vulnerability demonstrates the critical importance of maintaining up-to-date third-party libraries and implementing robust security controls to prevent exploitation of known weaknesses in widely used open source components.