Description

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Easy Appointments allows DOM-Based XSS. This issue affects Easy Appointments: from n/a through 4.0.2.1.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.1",
  "pubDate": "2026-09-08T08:17:13.013Z",
  "pubdate": "2026-09-08T08:17:13.013Z",
  "executiveSummary": "The Easy Appointments application is susceptible to a DOM-based Cross-Site Scripting (XSS) vulnerability, classified as Improper Neutralization of Input During Web Page Generation.\nThis vulnerability resides within the client-side code, where unsanitized user-supplied input is processed by insecure Document Object Model (DOM) APIs.\nSuccessful exploitation allows an attacker to execute arbitrary JavaScript within the context of the victim's browser session.\nThe vulnerability affects Easy Appointments versions from n/a through 4.0.2.1.\nImpacts include potential session hijacking, unauthorized actions performed on behalf of the user, theft of sensitive authentication tokens (such as cookies), and the redirection of users to malicious external domains.\nThe risk is high for users interacting with manipulated links or injected content within the application interface, as the malicious payload executes locally in the victim's browser without requiring server-side interaction.",
  "technicalDetails": "The vulnerability is identified as a DOM-based Cross-Site Scripting (XSS) flaw, stemming from the application's failure to properly sanitize or validate data before passing it to an 'execution sink'.\nIn DOM-based XSS, the vulnerability exists entirely in the client-side code. The server-side response remains unchanged, but the client-side JavaScript extracts data from an untrusted source—typically the URL fragment, query parameters, or other DOM elements—and passes it to a sink, such as innerHTML, document.write(), or eval().\nThe attack flow begins when an attacker crafts a malicious URL containing a JavaScript payload, often embedded within a query parameter or URL fragment (hash). When an authenticated or unauthenticated user clicks this link, the Easy Appointments client-side script parses the location object.\nBecause the application fails to perform input neutralization or output encoding at the point of execution, the malicious payload is interpreted by the browser as executable code rather than plain text.\nOnce the payload is executed in the Document Object Model, the attacker gains the ability to manipulate the page content, scrape data displayed on the screen, or intercept sensitive information.\nCommon exploitation vectors include the modification of the window.location or document.referrer attributes to inject arbitrary scripts. The payload can then access document.cookie to steal session identifiers, perform unauthorized requests via XMLHttpRequest or the Fetch API, or modify the DOM structure to present phishing interfaces to the user.\nThis vulnerability is particularly dangerous as it bypasss traditional server-side Web Application Firewalls (WAFs) that only inspect HTTP request payloads, as the exploit is delivered via the client-side navigation process.\nThe affected component involves the client-side JavaScript files responsible for dynamic page content rendering. Since the vulnerability is located in the DOM processing logic, it is present across versions 4.0.2.1 and earlier, regardless of server-side platform configurations, provided the vulnerable JavaScript code is served to the client."
}