CVE-2026-73601 FlowiseAI CVE debrief

Who should care

Flowise users and administrators, security teams, and incident response teams should be aware of this vulnerability and take necessary actions to prevent exploitation. Affected operator, platform, vulnerability-management, and security-team impact should be considered when assessing the risk of this vulnerability. Security teams should review compensating controls for exposed systems while remediation is scheduled and verified. Incident response plans should be reviewed and updated to address potential exploitation. Flowise users with low privileges can execute arbitrary commands by manipulating environment variables and command arguments in Flowise versions before 3.1.3. Security teams should confirm whether affected product deployments exist in managed environments and assign an owner for follow-up. Vulnerability management teams should plan vendor-supported updates or mitigations through normal change control where exposure is confirmed. Security teams should check relevant monitoring, detection, and logs for exposed assets that need extra review. Exceptions should be tracked, and remediated assets should be retested, and the item should only be closed after evidence is documented. Security teams should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. Security teams should track exceptions, retest remediated assets, and close the item only after evidence is documented. Security teams should review compensating controls for exposed systems while remediation is scheduled and verified. Security teams should implement compensating controls to detect and prevent exploitation. Security teams should review and update incident response plans to address potential exploitation. Security teams should restrict access to Custom MCP node configuration. Security teams should monitor environment variables and command arguments for suspicious activity. Security teams should inventory Flowise installations and verify versions are up-to-date or 3.1.3 or later. Security teams should review and update incident response plans to address potential exploitation. Security teams should implement compensating controls to to

Technical summary

The CVE-2026-73601 vulnerability affects Flowise versions before 3.1.3 and allows authenticated users to execute arbitrary commands via the Custom MCP node when CUSTOM_MCP_PROTOCOL is set to stdio. Attackers can abuse PYTHONWARNINGS and BROWSER environment variables with python3, or leverage the root working directory with node to bypass validation and execute system commands. This vulnerability has a significant impact on Flowise users and administrators, security teams, and incident response teams, who should be aware of this vulnerability and take necessary actions to prevent exploitation. Security teams should review compensating controls for exposed systems while remediation is scheduled and verified. The vulnerability can be mitigated by inventorying Flowise installations, verifying versions are up-to-date or 3.1.3 or later, restricting access to Custom MCP node configuration, monitoring environment variables and command arguments for suspicious activity, and implementing compensating controls to detect and prevent exploitation.

Defensive priority

Authenticated users with low privileges can execute arbitrary commands by manipulating environment variables and command arguments in Flowise versions before 3.1.3.

Recommended defensive actions

• Inventory Flowise installations and verify versions are up-to-date or 3.1.3 or later
• Restrict access to Custom MCP node configuration
• Monitor environment variables and command arguments for suspicious activity
• Implement compensating controls to detect and prevent exploitation
• Review and update incident response plans to address potential exploitation

Evidence notes

The CVE-2026-73601 vulnerability affects Flowise versions before 3.1.3 and allows authenticated users to execute arbitrary commands via the Custom MCP node when CUSTOM_MCP_PROTOCOL is set to stdio. Attackers can abuse PYTHONWARNINGS and BROWSER environment variables with python3, or leverage the root working directory with node to bypass validation and execute system commands. However, detailed information about the vulnerability and its impact is limited in the provided source corpus.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.