What this actually is.
Technical background, root cause, and affected surface.
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.
- Vendor
- X2CRM
- Affected Product
- X2CRM
- CVE
- CVE-2021-33853
- Securin ID
- 2021-CSW-11-1054
- Status
- Fixed
- Date
- December 1, 2021
- Severity
- Medium
- CVSS Score
- 5.4
- Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
- CWE
- CWE-79
From one request
to root shell.
Reproduced in a sandboxed environment. Requires only LAN or WiFi adjacency.
What an attacker does to you.
Post-exploitation outcomes mapped to CVSS impact metrics.
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.
Fix it. In this order.
A runbook, not a checklist. Sequence matters — assume compromise before you act.
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.
disclose@securin.ioVendors moved in days.
Attackers in hours.
Reconstructed from vendor advisories, CISA bulletins, and Securin research records.
Discovered in X2CRM 8.0` Product
CSW team reported to Vendor about the vulnerability.
X2CRM team postponed the release of X2CRM 8.5.
Vendor fixed the issue.
CSW assigned the CVE Identifier (CVE-2021-33853).
Timeline recorded · Disclosure coordinated by Securin
Cite, verify, go deeper.
Primary sources — NVD, CISA KEV, and machine-readable IoC feed.