Langflow - Authentication Bypass (CVE-2026-21445)

CVE-2026-21445 is a critical authentication bypass vulnerability in Langflow, a platform for building and deploying AI-powered agents and workflows. This flaw allows unauthenticated attackers to access sensitive user conversation data, transaction histories, and perform destructive actions such as message deletion via unprotected API endpoints. Exploitation of this vulnerability could lead to significant data breaches and unauthorized manipulation of user or system data. Upgrading to version 1.7.0.dev45 is strongly recommended to mitigate these risks.

CrowdSec has been tracking this vulnerability and its exploits since 1st of April 2026.

CrowdSec network observations suggest that most exploitation of CVE-2026-21445 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-2026-21445 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.

Attackers exploit unauthenticated access to the /api/v1/monitor/messages endpoint to retrieve sensitive user conversation data and message histories without authorization.