The jQWidgets vulnerability , documented as CVE-2026-78178, allows remote modification of JavaScript prototype properties via the object merging helper mechanism. The SecNews technical team is investigating what the finding means for applications that load settings, dashboards, or user data.
jQWidgets , and business environments. According to the NVD entry, the vulnerability affects versions 24.0.0 and 24.0.1 and has a CVSS score of 7.3, in the high severity category.
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The jQWidgets vulnerability and the merging mechanism
The issue is located in the JQXLite.extend and jqxBaseFramework.extend, inside the jqxcore.js and jqx-all.js. When the deep merge function receives an object controlled by a third party, the code reads and copies keys without excluding __proto__, constructor , and prototype.
This creates the risk of prototype pollution. Simply put, an attacker can add properties to Object.prototype, the common template from which many objects in the same JavaScript process inherit. The corrupted properties can then affect controls, default settings, or the flow of the application.
The jQWidgets vulnerability does not mean that every application that loads the library is automatically exposed. The risk increases when the application passes untrusted data to these functions, for example, settings from users, project files, JSON from a remote system, or parameters from different tenants.
What does CVE-2026-78178 report?
NVD records a network attack vector, low complexity, and no required privileges or user interaction. This description captures the potential severity, but the actual exposure depends on whether an application exposes its merge functions to attacker-controlled inputs.
The technical issue is documented in a technical report in the project repository. The report explains that reading the target object before checking for dangerous keys can lead to a recursive write to the shared prototype. If successfully exploited, this can change the behavior of objects created later or cause a denial of service.
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The same issue is listed as closed with the indication not planned. There is no available fix, commit or official package that resolves CVE-2026-78178. The SecNews technical team did not find a clear upgrade instruction on the available project pages, so the responsible parties should not assume that a newer version has fixed the problem without relevant confirmation.
Temporary defense for applications
Until a documented fix is available, development teams should avoid deep merging untrusted objects with these functions. The __proto__, constructor , and prototype should be discarded before any reads or writes, not after the merge is complete.
It is also recommended to check ownership with Object.keys and hasOwnProperty, avoid recursive merging on inherited objects, and use dictionaries with zero prototypes where possible. Security tests should confirm that no input can alter Object.prototype.
Administrators can check whether version 24.0.0 or 24.0.1 is being used, restrict entry points that accept JSON, and monitor for unusual configuration changes or application errors. Process isolation and strict schema validation reduce the impact, but are not a substitute for the official patch.
At the same time, teams should record where in the application they use extension functions and whether their data comes from forms, files, or APIs. Reviewing the jQWidgets repository and monitoring new releases is essential, as the current technical report does not describe an available fix pack.
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The main conclusion about the jQWidgets vulnerability is that the lack of a patched version requires a well-informed assessment of how the library is being used. Those accepting external configurations should not wait passively: they need to immediately restrict dangerous keys, control inputs, and monitor for available updates from the project.
