CVE-2026-104334: Critical Langflow OSS RCE

How to Detect It

Start by identifying every Langflow service and comparing its running version with the affected range. Include reverse proxies, ingress controllers, cloud load balancers, service meshes, and security groups so that teams can determine whether the application was reachable from untrusted networks.

Host-level telemetry is particularly valuable because successful code execution may appear as a process or filesystem event rather than a distinctive HTTP request. Monitor for Langflow spawning shells, interpreters, download utilities, or unexpected package managers. Review changes to flow definitions, configuration files, tokens, environment files, and mounted data directories.

Organizations can structure detection and response activities around the NIST Cybersecurity Framework, particularly its Identify, Protect, Detect, and Respond functions.

Technical Notes

Example Linux process triage commands include:

ps -eo pid,ppid,user,lstart,args --forest | \
  grep -Ei 'langflow|python|bash|sh|curl|wget|nc|socat'

sudo journalctl --since "24 hours ago" --no-pager | \
  grep -Ei 'langflow|auto_login|validate/code|exec|subprocess|traceback'

For EDR or SIEM correlation, search for a Langflow process spawning command interpreters or network utilities:

parent_process_name IN ("langflow", "python", "uvicorn")
AND child_process_name IN ("sh", "bash", "cmd.exe", "powershell.exe",
                           "curl", "wget", "nc", "socat", "python")

Review HTTP logs for requests to /api/v1/auto_login and /api/v1/validate/code, unusual request bodies, repeated authentication failures followed by successful token issuance, and requests originating from unexpected source addresses. Preserve logs before restarting or rebuilding a potentially compromised instance.

For endpoint validation after suspicious activity, a reputable malware-detection product such as Malwarebytes may complement existing EDR and SIEM controls, but it should not replace forensic review.

Mitigation and Patching

The confirmed affected range is 1.0.0 through 1.12.2. A definitive fixed version was not present in the retrieved NVD material or the portion of IBM’s advisory reviewed for this article. Administrators must consult IBM’s security bulletin for the vendor-designated remediated release and validate that release in a test environment before broad deployment.

Until the fixed version is confirmed and applied, restrict Langflow to trusted administrative networks. Do not expose the service directly to the internet. Enforce authentication at the application and reverse-proxy layers, limit administrative API access, remove unnecessary public ingress rules, and isolate the service from sensitive internal systems.

Technical Notes

After IBM identifies the fixed release, use the exact version in a controlled deployment rather than guessing a version number:

python -m pip install --upgrade 'langflow==<IBM-confirmed-fixed-version>'
python -m pip check
python -m pip show langflow

For container deployments, replace the image reference with the vendor-confirmed remediated tag or digest, then recreate the workload:

docker pull <vendor-confirmed-langflow-image>:<fixed-tag>
docker compose up -d --force-recreate langflow
docker exec <langflow-container> python -m pip show langflow

The placeholder is intentional: the available research does not establish a safe fixed version. Do not substitute 1.12.3 or another release without explicit IBM confirmation.

As an interim network control, restrict access at the reverse proxy or firewall. For example, an Nginx deployment can permit only an internal management network:

location / {
    allow 10.20.0.0/16;
    deny all;
    proxy_pass http://langflow_backend;
}

After patching, rotate secrets available to the Langflow process if the instance was internet-exposed, showed suspicious activity, or cannot be proven clean. Rebuild compromised containers or hosts from trusted images rather than assuming that an upgrade removes persistence.

If an investigation confirms compromise, follow a documented incident-response process and isolate affected systems before rebuilding them. Organizations can also review the guidance in What should I do after a ransomware attack? for broader containment, evidence-preservation, and recovery considerations.

References

The primary references for this issue are the NVD record and IBM’s security bulletins. The NVD description identifies IBM Langflow OSS 1.0.0 through 1.12.2 as affected and describes the issue as improper control of code generation that may allow a remote attacker to execute arbitrary code.

• NVD: CVE-2026-104334
• IBM Security Bulletin: Langflow OSS affected by multiple vulnerabilities
• IBM advisory reference
• CISA Known Exploited Vulnerabilities Catalog

The exploitation status in this article is deliberately conservative. CISA KEV did not list the CVE during the reviewed lookup, no vendor-confirmed exploitation was identified, and the third-party endpoint report was not independently validated. Recheck IBM, NVD, and CISA before making final remediation or incident-response decisions.

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