CVE-2020-7642: Cross-site scripting in lazysizes
Summary
CVE-2020-7642: Cross-site scripting in lazysizes. Affects lazysizes versions < 5.2.1. Fixed in 5.2.1. How to fix ↓
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Background
lazysizes is an npm package that provides lazy loading functionality for images and videos on websites. It allows developers to delay the loading of media content until it is needed, improving page load times and overall performance. However, lazysizes versions up to 5.2.0 are vulnerable to a cross-site scripting (XSS) attack. This vulnerability arises from the video-embed plugin's failure to sanitize certain attributes, including data-vimeo, data-vimeoparams, data-youtube, and data-ytparams. An attacker can exploit this vulnerability to inject and execute malicious JavaScript code.
Vulnerability Detail
The vulnerability in lazysizes versions up to 5.2.0 allows an attacker to execute arbitrary JavaScript code on a victim's browser. By injecting malicious code through the unsanitized attributes mentioned above, an attacker can potentially steal sensitive information, perform unauthorized actions on behalf of the victim, or manipulate the website's content. This vulnerability has a CVSS score of 5.4, indicating a moderate severity level.
How To Fix
Minimum fixed version
5.2.1
This is the first release that contains the fix.
npm install lazysizes@5.2.1Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If upgrading to the latest version is not immediately feasible, a temporary workaround is to manually sanitize the vulnerable attributes before using them. This can be done by implementing input validation and escaping techniques to prevent the execution of malicious JavaScript code. Here is an example of how to sanitize the 'data-vimeo' attribute:
const sanitizeAttribute = (attribute) => {
return attribute.replace(/[<>&]/g, (c) => {
switch (c) {
case '<':
return '<';
case '>':
return '>';
case '&':
return '&';
}
});
};
const vimeoAttribute = sanitizeAttribute(videoElement.dataset.vimeo);
Conclusion
In conclusion, lazysizes versions up to 5.2.0 are vulnerable to a cross-site scripting (XSS) attack due to unsanitized attributes. This can allow an attacker to execute malicious JavaScript code on a victim's browser, potentially leading to various security risks. To mitigate this vulnerability, it is crucial to upgrade to lazysizes version 5.2.1 or later. Additionally, implementing input validation and escaping techniques can serve as a temporary workaround. For further assistance on vulnerability remediation, please contact DevNack.com.
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FAQ
lazysizes is an npm package that provides lazy loading functionality for images and videos on websites. It helps improve page load times by delaying the loading of media content until it is needed.
lazysizes versions up to 5.2.0 are affected by this vulnerability. It is recommended to upgrade to version 5.2.1 or later to fix the issue.
An attacker can exploit this vulnerability by injecting malicious JavaScript code through the unsanitized attributes, such as data-vimeo, data-vimeoparams, data-youtube, and data-ytparams. This can lead to the execution of arbitrary code on a victim's browser.
The potential consequences of this vulnerability include the theft of sensitive information, unauthorized actions performed on behalf of the victim, and manipulation of the website's content.
Yes, the developers have released lazysizes version 5.2.1, which addresses this vulnerability. It is recommended to upgrade to the latest version to ensure the application is secure.
References
Related vulnerabilities
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