CVE-2025-9796 in JeeSite
Summary
by MITRE • 09/02/2025
A vulnerability was found in thinkgem JeeSite up to 5.12.1. This affects the function decodeUrl2 of the file common/src/main/java/com/jeesite/common/codec/EncodeUtils.java. The manipulation results in cross site scripting. It is possible to launch the attack remotely. The exploit has been made public and could be used. Upgrading to version 5.13.0 mitigates this issue. The patch is identified as 63773c97a56bdb3649510e83b66c16db4754965b. Upgrading the affected component is recommended.
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Analysis
by VulDB Data Team • 09/05/2025
CVE-2025-9796 represents a cross-site scripting vulnerability in thinkgem JeeSite version 5.12.1 and earlier, specifically within the decodeUrl2 function located in common/src/main/java/com/jeesite/common/codec/EncodeUtils.java. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which occurs when an application incorporates untrusted data into web pages without proper validation or encoding, allowing malicious scripts to be executed in the context of other users' browsers. The flaw exists in the URL decoding functionality that processes user-supplied input, creating an attack surface where malicious payloads can be injected through URL parameters and subsequently executed when the application processes these inputs.
The technical implementation of this vulnerability stems from inadequate input sanitization within the decodeUrl2 method, which fails to properly escape or validate special characters that could be interpreted as HTML or JavaScript code. When the application processes URLs containing malicious payloads, the decodeUrl2 function does not sufficiently sanitize the decoded content before rendering it in web pages, enabling attackers to inject script tags, event handlers, or other malicious code that executes in the victim's browser context. This vulnerability is particularly dangerous because it can be exploited remotely through web-based attack vectors without requiring any special privileges or access to the target system.
The operational impact of this vulnerability is significant, as it allows remote attackers to execute arbitrary JavaScript code in the browsers of users who interact with the affected application. Attackers can leverage this weakness to perform session hijacking, deface web pages, steal sensitive information, redirect users to malicious sites, or conduct further attacks against the application or its users. The fact that an exploit has been made public increases the risk profile considerably, as it provides attackers with ready-made tools and techniques to target vulnerable installations. The vulnerability affects the core functionality of the application's encoding utilities, which are likely used throughout the application for processing user input, making the attack surface broader than initially apparent.
Security mitigations for this vulnerability are straightforward and involve upgrading to JeeSite version 5.13.0 or later, which contains the patched implementation of the decodeUrl2 function. The patch identified by commit hash 63773c97a56bdb3649510e83b66c16db4754965b addresses the root cause by implementing proper input validation and output encoding mechanisms. Organizations should also implement additional defensive measures including input validation at multiple layers, output encoding for all user-supplied content, regular security assessments, and monitoring for suspicious activities. The ATT&CK framework categorizes this vulnerability under T1203 Exploitation for Client Execution, highlighting the importance of securing web application input handling mechanisms. System administrators should prioritize patching this vulnerability and consider implementing web application firewalls to provide additional protection against similar attacks targeting the application's web interface components.