Description
Drupal Core is prone to a cross-site scripting vulnerability because it fails to properly sanitize user-supplied input. An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This can allow the attacker to steal cookie-based authentication credentials and launch other attacks. Drupal Core versions 8.6.x ranging from 8.6.0 and up to and including 8.6.12 are vulnerable.
Remediation
Update to Drupal Core version 8.6.13 or latest
References
https://github.com/thezdi/PoC/blob/master/Drupal/drupal_xss_rce.zip
Related Vulnerabilities
Apache Traffic Server Improper Input Validation Vulnerability (CVE-2021-41585)
Dolibarr Authorization Bypass Through User-Controlled Key Vulnerability (CVE-2021-3991)
Squid Improper Input Validation Vulnerability (CVE-2020-8517)
WordPress Plugin WP Customer Area Cross-Site Scripting (7.4.2)
WordPress Plugin Social Metrics Tracker Cross-Site Scripting (1.6.8)