CVE-2026-56274: Critical OS Command Injection in FlowiseAI Flowise

Detection and Investigation Guidance

Detection should focus on three areas: suspicious chatflow changes, anomalous process execution by the Flowise service account, and abnormal outbound connections or local file access following MCP server configuration activity. Because the public description ties exploitation to malicious MCP server configuration, audit trails related to chatflow updates and MCP settings are likely to be your highest-value application-level evidence.

At the host level, investigate whether the Flowise process spawned unexpected child processes such as shell interpreters, package managers, container tooling, or download utilities. The public examples specifically call out docker build and npx --yes, so those strings should be treated as meaningful hunting pivots. Also review for command execution shortly after authenticated API calls or UI-driven chatflow modifications.

Technical Notes

If Flowise logs API requests or configuration updates, look for changes touching MCP server settings, chatflow updates, or suspicious command-like values in request bodies. Exact field names may vary by deployment, so defenders should search broadly around MCP-related routes and payload content.

Example generic log hunting patterns:

mcp
MCP Server
chatflow update
validateCommandFlags
validateArgsForLocalFileAccess
docker build
npx --yes

Example EDR or process-hunting pivots on Linux:

ps -ef | egrep 'flowise|node|npm|npx|docker|sh|bash'
journalctl -u flowise --since "7 days ago"
grep -R -E 'docker build|npx --yes|/bin/sh|/bin/bash' /var/log 2>/dev/null

Example Splunk search for suspicious child process execution from a Flowise or Node.js parent:

index=* (process_name=node OR parent_process_name=node OR process_name=flowise OR parent_process_name=flowise)
(command_line="*docker build*" OR command_line="*npx --yes*" OR command_line="*/bin/sh*" OR command_line="*/bin/bash*")

Example Sigma-style idea for adaptation:

title: Suspicious Flowise Child Process Execution
logsource:
  product: linux
  category: process_creation
detection:
  selection_parent:
    ParentImage|contains:
      - "node"
      - "flowise"
  selection_cmd:
    CommandLine|contains:
      - "docker build"
      - "npx --yes"
      - "/bin/sh"
      - "/bin/bash"
  condition: selection_parent and selection_cmd
level: high

If you do not have rich process telemetry, fall back to reviewing recent Flowise user activity, API token usage, and any config backups or database records storing chatflow or MCP definitions. In the absence of published IoCs from the vendor, defenders should assume detection will rely on behavioral evidence rather than signature-perfect matching.

Mitigation and Patching

The primary mitigation is to upgrade Flowise to version 3.1.2 or later immediately. Since the affected range is stated as before 3.1.2, there is no evidence in the provided sources that partial configuration changes alone fully eliminate risk on vulnerable builds. If you are running a version < 3.1.2, treat patching as the required long-term fix.

If an immediate upgrade is not possible, reduce exposure by restricting access to Flowise accounts and API tokens, especially those with view/update permissions for chatflows. Review whether the Custom MCP Server feature can be disabled or administratively restricted in your environment. Because the available source set does not provide an official temporary workaround from the vendor, defenders should assume that compensating controls lower risk but may not completely prevent exploitation.

You should also rotate exposed credentials if compromise is suspected. Flowise instances often hold secrets for LLM providers, vector stores, databases, and internal APIs. A host-level command execution bug creates a realistic path to secret harvesting. In parallel, isolate the host if suspicious process execution or unauthorized chatflow changes are found.

Technical Notes

Upgrade commands will depend on how Flowise is deployed. The exact vendor-preferred upgrade path is not fully described in the provided source set, so use your established deployment method and verify that the resulting version is 3.1.2 or later.

Examples for common self-hosted approaches:

# If deployed via npm in your environment
npm install -g flowise@3.1.2
flowise --version

# If using Docker and tagging explicitly
docker pull flowiseai/flowise:3.1.2
docker stop flowise
docker rm flowise
docker run -d --name flowise -p 3000:3000 flowiseai/flowise:3.1.2

# If using Docker Compose, update the image tag to 3.1.2 and redeploy
sed -i 's#flowiseai/flowise:.*#flowiseai/flowise:3.1.2#' docker-compose.yml
docker compose pull
docker compose up -d

If you cannot patch immediately, apply temporary access reduction steps:

# Example reverse proxy allowlisting for admin/internal networks only
# Adjust for your environment before use
ufw allow from 10.0.0.0/8 to any port 3000
ufw deny 3000/tcp

Also revoke or rotate API tokens with chatflow update capability, and disable unnecessary user accounts. After upgrading, verify the version directly from the application or deployment metadata rather than assuming the package pull succeeded.

Incident Response Considerations

If you suspect exploitation, investigate beyond the Flowise application itself. A successful attack may leave evidence in shell history, temporary directories, container build caches, npm caches, cron entries, systemd unit changes, or newly dropped binaries. Because this is arbitrary command execution, there is no reason to assume attacker activity stayed within the application boundary.

Prioritize scoping around secrets exposure. Review environment variables, mounted files, .env files, cloud instance roles, SSH keys, CI tokens, and any connectors configured in Flowise. If the host had access to downstream systems, extend your investigation to those systems as well. In many real incidents, the initial RCE is less damaging than the follow-on credential abuse.

References