BeyondTrust Secure Remote Access - XSS (CVE-2021-31589)

CVE-2021-31589 is a cross-site scripting (XSS) vulnerability affecting BeyondTrust Secure Remote Access. It enables attackers to inject unauthenticated, specially crafted web requests through insufficient sanitization in the login interface.

CrowdSec has been tracking this vulnerability and its exploits since 31st of March 2025.

CrowdSec network observations suggest that most exploitation of CVE-2021-31589 involves focused reconnaissance to identify viable targets. Attackers typically tailor their campaigns based on system exposure and configuration. It is unlikely that a given attack is accidental. CrowdSec network telemetry also shows that exploitation of CVE-2021-31589 has significantly declined over the past week. Attack volumes are well below the long-term average, suggesting attackers are rapidly losing interest. The vulnerability appears to be falling out of active use across most threat landscapes.

Observed exploitation attempts target URLs containing /appliance/login.ns.