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medium·Product Based Web Vulnerabilities·Updated Sep 16, 2025

CVE-2021-24876 Scanner

CVE-2021-24876 Scanner - Cross-Site Scripting (XSS) vulnerability in Registrations for The Events Calendar

Est. Time~10 seconds
Scan TypeSingle Scan
Targetsdomain, subdomain, ipv4
CostFree
2.5k
Times Used
continuous scan runs
4.8k
Continuously Checked
assets under CS
0
Vulnerabilities Found
confirmed findings
References
CVECVE-2021-24876
6.1
CVSS

The Registrations for the Events Calendar WordPress plugin before 2.7.5 does not escape the v parameter before outputting it back in an attribute, leading to a Reflected Cross-Site Scripting

Attack Vector
-
Privileges Req.
-
User Interaction
-
Affected
Registrations for the Events Calendar – Event Registration Plugin
AFFECTED< 2.7.5SAFE ✓≥ 2.7.5
Updated Aug 21, 2026View on NVD →
Detail

The Registrations for The Events Calendar plugin is widely used in WordPress for managing event registrations. It is commonly used by website administrators to facilitate event management on their platforms. The plugin helps in organizing, displaying, and managing events efficiently. Due to its popularity, it is essential for web managers to ensure it is secure and updated. Being an integral part of event management solutions, security is paramount to protect user data and maintain trust. The vulnerability in question, therefore, attracts significant attention for timely detection and remediation.

Cross-Site Scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users. In this specific case, the vulnerability is a reflected XSS, which means the script is reflected off a web server. It occurs when the plugin fails to escape certain parameters before outputting them back in a page. Such vulnerabilities can be exploited to execute arbitrary scripts in a user's browser. This can lead to unauthorized actions being taken on behalf of the user or the unauthorized collection of data.

Technically, the vulnerability involves the 'v' parameter, which is not properly escaped. This parameter can be manipulated to include malicious scripts that will be executed when the page is rendered in a browser. The attack requires sending a specially crafted URL to an authenticated user who has a certain privilege. Once the link is clicked, the injected script is executed in the context of the user's session. The flaw is evident in the handling of input that is reflected back into the HTML output without proper sanitization.

If exploited, this vulnerability can lead to severe consequences such as session hijacking or defacement. Users might unknowingly execute malicious scripts, leading to unauthorized access of their logged-in sessions. Attackers could steal sensitive data such as cookies, which can be used to impersonate users. Additionally, the site could be used to serve malware to users. The integrity and reputation of the affected website can also be compromised.

REFERENCES

Solution Advice
  • Update the Registrations for The Events Calendar plugin to version 2.7.5 or later to patch this vulnerability.
  • Sanitize and validate all input fields, especially those that involve user-generated content being reflected in web output.
  • Implement Content Security Policies (CSP) to restrict which scripts can be executed by the browser.
  • Regularly audit and test web applications and plugins for security vulnerabilities.
  • Educate users on the dangers of clicking on untrusted links to prevent such attacks.

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CVE-2021-24876 Scanner - Cross-Site Scripting (XSS) vulnerability in Registrations for The Events Calendar | S4E