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CVE-2021-33853 - Stored Cross-Site Scripting in X2CRM

Affected Vendor





Dec 1, 2021

Medium Severity


A Cross-Site Scripting (XSS) attack can cause arbitrary code (javascript) to run in a user’s browser while the browser is connected to a trusted website. As the vehicle for the attack, the application targets the users and not the application itself. Additionally, the XSS payload is executed when the user attempts to access any page of the CRM.

Proof of concept: (POC)

The following vulnerability was discovered in X2CRM version 8.0.

Issue: Stored Cross-Site Scripting

  1. Login to the X2CRM as administrator.

  2. Go to the “Administrator” tool and click on the “User Interface Management’’ submenu and select “Add Top Bar Link”.

Figure 1: Add Top Bar Page

  1. Enter “<script>alert(“XSS”)</script>” in the “Link Name” field and submit the request.

Figure 2: Payload injected in “Link Name” field

  1. By accessing any page within the CRM, the payload will be executed.

Figure 3: XSS Payload Triggered


An attacker can perform the following -

  • Inject malicious code into the vulnerable variable and exploit the application through the Cross-Site Scripting vulnerability.

  • Modify the code and get the session information of other users.

  • Compromise the user machine.


  • Perform context-sensitive encoding of entrusted input before echoing back to a browser using an encoding library throughout the application.

  • Implement input validation for special characters on all the variables are reflected in the browser and stored in the database.

  • Explicitly set the character set encoding for each page generated by the webserver.

  • Encode dynamic output elements and filter specific characters in dynamic elements.


November 11, 2021: Discovered in X2CRM 8.0` Product

December 1, 2021: CSW team reported to Vendor about the vulnerability.

January 20, 2022: X2CRM team postponed the release of X2CRM 8.5.

February 1, 2022: Vendor fixed the issue.

February 1, 2022: CSW assigned the CVE Identifier (CVE-2021-33853).

Discovered by

Cyber Security Works Pvt. Ltd.

  • Affected VendorX2CRM
  • Bug NameStored Cross-Site Scripting
  • CVE NumberCVE-2021-33853
  • CWE IDCWE-79
  • CSW ID2021-CSW-11-1054
  • CVSSv3 Score6.1
  • Affected VersionVersion 8.0
  • SeverityMedium
  • Affected ProductX2CRM
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