CVE-2015-9251 in Retail Customer Management
Summary
by MITRE
jQuery before 3.0.0 is vulnerable to Cross-site Scripting (XSS) attacks when a cross-domain Ajax request is performed without the dataType option, causing text/javascript responses to be executed.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/30/2025
The vulnerability identified as CVE-2015-9251 represents a critical cross-site scripting flaw in jQuery versions prior to 3.0.0 that specifically affects cross-domain ajax requests. This vulnerability stems from the library's handling of javascript responses when no explicit dataType parameter is specified in ajax calls. The flaw creates a dangerous condition where malicious actors can inject arbitrary javascript code that gets executed in the context of the victim's browser, potentially leading to session hijacking, data theft, or complete compromise of user sessions.
The technical root cause of this vulnerability lies in jQuery's default response handling behavior when processing cross-domain requests. When developers omit the dataType option in their ajax calls, jQuery automatically infers the response type based on the content received from the server. In cross-domain scenarios, if the server returns a text/javascript response without proper content-type headers or explicit dataType specification, jQuery treats this response as executable javascript code. This automatic execution behavior creates an attack surface where malicious servers can deliver javascript payloads that get interpreted and executed by the victim's browser, bypassing normal security restrictions that would typically prevent such code execution.
The operational impact of CVE-2015-9251 extends beyond simple script execution, as it can enable sophisticated attack chains that leverage the attacker's ability to manipulate the response content. Attackers can exploit this vulnerability by setting up malicious servers that return javascript content in response to cross-domain ajax requests, potentially leading to full browser compromise. The vulnerability affects not just simple XSS scenarios but can facilitate more complex attacks including session theft, credential harvesting, and even browser-based malware delivery. This makes it particularly dangerous in environments where users interact with multiple domains or where ajax calls are made to untrusted third-party services.
Security professionals should note that this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications. The attack pattern follows typical XSS methodologies described in the MITRE ATT&CK framework under the technique of "Cross-site Scripting" (T1059.002). Organizations using affected jQuery versions should immediately upgrade to jQuery 3.0.0 or later, as this version implements proper response type handling that prevents automatic execution of javascript content in cross-domain scenarios. Additional mitigations include implementing proper content-type headers on all server responses, using explicit dataType specifications in ajax calls, and employing Content Security Policy headers to limit script execution. The vulnerability serves as a critical reminder of the importance of proper input validation and response handling in web frameworks, particularly when dealing with cross-domain communications where the security context can be easily compromised.