CVE-2018-19057: simplemde - XSS Vulnerability
Summary
CVE-2018-19057: SimpleMDE XSS Vulnerability. Affects simplemde versions < 1.11.2. No fix is published. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
SimpleMDE is a JavaScript library that provides a simple and elegant Markdown editor for web applications. It allows users to input and edit Markdown text, providing a live preview of the rendered HTML. The library is widely used in various web applications to enhance the user experience of editing and formatting text content. However, SimpleMDE versions up to 1.11.2 are vulnerable to a cross-site scripting (XSS) attack.
Vulnerability Detail
The vulnerability in SimpleMDE arises from the mishandling of certain input during the construction of an A (anchor) element. This can be exploited through an onerror attribute of a crafted IMG (image) element or by using specific input with [ and ( characters. An attacker can inject malicious code into the generated HTML, which will be executed in the context of the user's browser. This can lead to various consequences, such as the theft of sensitive information, session hijacking, or the execution of arbitrary actions on behalf of the user.
How To Fix
No fixed version is published for this vulnerability.
Tip — Not sure whether your app is affected? Vulert can check the versions your app actually runs. Scan free →
Workaround
If upgrading SimpleMDE is not immediately feasible, a temporary workaround can be implemented by manually sanitizing the input before passing it to SimpleMDE. This can be done by using a library or function that escapes or removes any potentially dangerous characters or tags. Here is an example of how to sanitize user input using the 'sanitize-html' library in Node.js:
const sanitizeHtml = require('sanitize-html');
const sanitizedInput = sanitizeHtml(userInput);
Conclusion
The XSS vulnerability in SimpleMDE versions up to 1.11.2 can have serious security implications for web applications using this library. It is crucial to promptly address this vulnerability by upgrading to a patched version of SimpleMDE. Developers should also ensure that user input is properly sanitized to mitigate the risk of XSS attacks. For further support and assistance in vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for simplemde →
FAQ
SimpleMDE is a JavaScript library that provides a Markdown editor for web applications, allowing users to input and edit Markdown text with a live preview.
Cross-site scripting (XSS) is a type of security vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users. This can lead to the theft of sensitive information or the execution of unauthorized actions.
The XSS vulnerability in SimpleMDE occurs due to the mishandling of certain input during the construction of an A (anchor) element. This allows an attacker to inject malicious code into the generated HTML, which is executed in the user's browser.
The potential consequences of this vulnerability include the theft of sensitive information, session hijacking, and the execution of arbitrary actions on behalf of the user.
To protect your application from this vulnerability, it is recommended to upgrade SimpleMDE to a version that includes the necessary security patches. Additionally, input should be properly sanitized before passing it to SimpleMDE.
