CVE-2026-0769

This vulnerability is like a “back door” in Langflow’s evaluation feature: if someone can reach it, they can trick it into running their own code on your server. That can lead to your system being fully controlled, similar to handing an attacker the keys to the server.

This matters if you run Langflow and your server is exposed to untrusted users. The vulnerability does not require authentication to trigger, so public reachability increases risk. Treat it as a risk when Langflow endpoints are reachable from the internet and the vulnerable evaluation path is available.

This is urgent because attackers have been reported exploiting this flaw (press attention notes exploitation), and the weakness allows remote code execution without a login. With no known fix information available yet, reducing exposure immediately is the priority for affected deployments.

Confirm whether you’re exposed

1. Identify all Langflow deployments (prod, staging, and any demo/internal instances that might be internet-accessible).
2. Determine whether any Langflow endpoint is reachable from the internet (directly or via a reverse proxy).
3. Review your configuration and usage for custom component evaluation features—specifically anything that corresponds to “eval_custom_component_code” behavior.

Contain risk immediately (until a fix exists)

4. Restrict network access to Langflow:
   • Remove public internet access (no world-writable exposure).
   • Allow only your office/VPN/bastion IPs (or authenticated corporate network paths).
5. If you can disable the custom evaluation capability tied to eval_custom_component_code, do so in your Langflow setup.
6. If you cannot disable it, keep Langflow fully off the public network and ensure only trusted sources can reach it.

Patch / upgrade path

7. No patch version information is currently available for CVE-2026-0769, so you should:
   • Monitor Langflow security advisories/releases specifically for this CVE.
   • Upgrade as soon as a fixed release becomes available.

What to monitor

8. Watch for evidence of malicious activity around the time of attempted access:
   • Reverse proxy access logs for unusual requests to Langflow-related endpoints.
   • Langflow application logs for errors tied to evaluation/custom components.
   • Server logs for unexpected process executions shortly after external requests.

CISA “known exploited” timeline

9. This CVE is not listed in the CISA KEV catalog based on the provided findings.

Overview

• CVE: CVE-2026-0769
• Product: Langflow
• Weakness: CWE-95 (Improper Neutralization of Input During Code Generation)

Mechanism / trigger

• The vulnerable implementation (eval_custom_component_code) uses a user-supplied string in a way that can result in Python code execution.
• The core issue is insufficient validation/neutralization of that input before it is executed, enabling remote code injection.

Attack characteristics

• Authentication is not required to exploit (as described in the backstop and aligned with PR:N).
• Remote attackers can execute arbitrary code in the context of the running Langflow process.

Exploitation status and maturity (from findings)

• No public exploit code is on record.
• There has been resurfacing press attention with exploitation as the reason (indicating real-world interest/attempted use).
• KEV: not listed in CISA KEV.

Patch status

• No fix/patch information is available in the provided findings, so exact fixed versions can’t be stated yet.

Likelihood signals

• EPSS was reported as a prediction with a rising trend; however, public EPSS figures are not used to drive urgency if exploitation is indicated. The working assumption for remediation should be “treat as actively relevant” until mitigation and fixed versions are confirmed.