Executive Summary

This vulnerability affects versions of the Svelte web framework prior to 5.51.5. It is a cross-site scripting (XSS) issue that occurs during server-side rendering when using spread syntax to render attributes from untrusted data. Specifically, event handler properties from user-controlled or external data are included in the rendered HTML output, allowing an attacker to inject malicious event handlers that execute in the browsers of users viewing the affected application.

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Impact Analysis

The vulnerability can allow attackers to execute malicious scripts in the browsers of users interacting with the affected application. This can lead to unauthorized actions, data theft, session hijacking, or other malicious activities performed on behalf of the victim without their consent.

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Compliance Impact

I don't know

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Detection Guidance

I don't know

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Mitigation Strategies

To mitigate this vulnerability, upgrade the svelte framework to version 5.51.5 or later, where the issue is fixed.

Additionally, avoid using spread syntax to render attributes from untrusted or user-controlled data, especially event handler properties, to prevent injection of malicious event handlers.

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