CVE-2016-10537 in backbone
Summary
by MITRE
backbone is a module that adds in structure to a JavaScript heavy application through key-value pairs and custom events connecting to your RESTful API through JSON There exists a potential Cross Site Scripting vulnerability in the `Model#Escape` function of backbone 0.3.3 and earlier, if a user is able to supply input. This is due to the regex that's replacing things to miss the conversion of things such as `<` to `<`.
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Analysis
by VulDB Data Team • 01/17/2026
The vulnerability identified as CVE-2016-10537 affects the Backbone JavaScript framework version 0.3.3 and earlier, specifically within the Model#Escape function implementation. This security flaw represents a classic cross-site scripting vulnerability that emerges from inadequate input sanitization mechanisms. The Backbone library serves as a structural framework for JavaScript applications, providing key-value pairs and custom events that facilitate connections to RESTful APIs through JSON data exchange. The affected version's Model#Escape function fails to properly handle HTML entity conversion, creating a pathway for malicious code injection through user-supplied input that is subsequently processed by the framework's escaping mechanism.
The technical root cause of this vulnerability lies in the regular expression pattern used within the Model#Escape function, which fails to account for all HTML special characters that require proper encoding for web security. Specifically, the regex pattern does not adequately convert the less-than character '<' to its HTML entity equivalent '<', allowing attackers to inject malicious scripts that can execute within the context of a victim's browser session. This oversight demonstrates a fundamental flaw in the security implementation where the escaping mechanism assumes that certain characters are properly handled while leaving critical HTML entities unescaped, creating a persistent XSS vulnerability that can be exploited across different application contexts.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers to manipulate the application's behavior and potentially access sensitive user data. When user input containing malicious scripts is processed through the Model#Escape function, the incomplete escaping allows these scripts to persist and execute within the browser environment, potentially leading to session hijacking, data theft, or further exploitation of the application's functionality. The vulnerability affects applications that rely on Backbone's data handling mechanisms, particularly those that do not implement additional input validation layers or that trust the framework's built-in escaping mechanisms without proper verification.
Security practitioners should recognize this issue as a variant of CWE-79, which specifically addresses cross-site scripting vulnerabilities, and it aligns with ATT&CK technique T1213.002 related to data from information repositories. The vulnerability demonstrates the importance of comprehensive input sanitization and the dangers of relying on incomplete escaping mechanisms. Organizations should immediately upgrade to Backbone versions that address this vulnerability, implement additional input validation layers, and conduct thorough security testing of all user-supplied content processing. The fix typically involves updating the regular expression patterns to properly handle all HTML special characters, including but not limited to '<', '>', '&', '"', and ''', ensuring complete sanitization of user input before it is processed by the framework's escaping functions.