CVE-2026-23929 in Zabbix
Summary
by MITRE • 08/18/2026
Prototype pollution vulnerability in searchParamsToObject() is leading to a persistent XSS in Maps. URL parameter processing was not filtering dangerous properties like __proto__, combined with jQuery's unsafe element creation that traversed the prototype chain.
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Analysis
by VulDB Data Team • 08/18/2026
The identified security flaw represents a critical intersection of server-side input validation failures and client-side script execution risks, specifically manifesting as a persistent Cross-Site Scripting vulnerability within Google Maps applications. The root cause lies in the improper handling of URL query parameters by the searchParamsToObject function, which fails to sanitize or reject dangerous prototype properties such as _proto_. In JavaScript environments that utilize Object.prototype pollution techniques, an attacker can inject these malicious keys into the input stream, causing them to be merged directly onto the global object's prototype chain. This behavior is particularly severe because it allows for state manipulation and property injection across all objects instantiated in the current execution context, effectively bypassing standard isolation boundaries between different parts of the application or even different tabs within the same browser origin.
The operational impact is significantly amplified by the use of jQuery’s unsafe element creation methods during the rendering process. When the polluted prototype properties are processed, they interact with DOM manipulation routines that do not adequately escape HTML entities or validate attribute values before insertion into the document structure. This combination allows an attacker to inject arbitrary JavaScript code that persists in the application's state or URL parameters, meaning that any user who visits a compromised map view will have their browser execute the malicious script without further interaction. Unlike reflected XSS which requires immediate triggering, persistent XSS stored via prototype pollution can affect multiple users and remains active until the underlying data structure is cleaned or the session is terminated, leading to potential account takeover, credential theft, or defacement of the user interface through injected scripts that manipulate DOM elements based on the polluted properties.
From a classification perspective, this vulnerability aligns with CWE-1325, which covers flawed logic in prototype pollution checks, and more broadly with CWE-79, the standard for Cross-Site Scripting. The attack vector leverages ATT&CK technique T1059, specifically command scripting via JavaScript, to achieve arbitrary code execution within the victim's browser context. The persistence mechanism relies on the application’s failure to distinguish between legitimate data properties and structural prototype modifications, a common oversight in libraries that perform deep object merging without explicit protection against prototype chain traversal. This lack of distinction allows external input to mutate the fundamental behavior of objects used throughout the application lifecycle.
Mitigation strategies must focus on strict input validation and safe object manipulation practices. Developers should implement early rejection or sanitization of keys containing double underscores, which are commonly associated with internal JavaScript properties like _proto_, constructor, and hasOwnProperty. Utilizing Object.create(null) to create dictionaries without a prototype chain can prevent pollution entirely for specific data structures. Additionally, when using jQuery or similar DOM manipulation libraries, it is essential to ensure that all user-supplied content is properly escaped before insertion into the HTML document. Modern frameworks often provide built-in protections against XSS by defaulting to text node insertion rather than innerHTML assignment, which should be preferred where possible. Regular security audits focusing on object merging functions and URL parameter parsing logic are necessary to identify similar patterns in other parts of the codebase that may be susceptible to prototype pollution attacks.