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LangflowApplication

CVE-2026-33873

CRITICAL · 9.9 CVSS v3.1 Published 2026-03-27
Fix available
A fix is available. Upgrade to 1.9.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.9.0, the Agentic Assistant feature in Langflow executes LLM-generated Python code during its validation phase. Although this phase appears intended to validate generated component code, the implementation reaches dynamic execution sinks and instantiates the generated class server-side. In deployments where an attacker can access the Agentic Assistant feature and influence the model output, this can result in arbitrary server-side Python execution. Version 1.9.0 fixes the issue.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Agentic Assistant feature in Langflow versions prior to 1.9.0 executes LLM-generated Python code during its validation phase, reaching dynamic execution sinks and instantiating generated classes server-side. This allows attackers who can access the feature and influence model output to achieve arbitrary server-side Python code execution.

MitigationUpgrade to Langflow version 1.9.0 or later. Until upgraded, restrict network access to the Agentic Assistant feature and disable it in untrusted deployments.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
LangflowApplication
Affected:< 1.9.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed Langflow version
    Run 'pip show langflow' or check your package manager for the installed langflow package version
    Affected if Version is lower than 1.9.0 (e.g., 1.8.x, 1.7.x, etc.)
  2. Locate Langflow configuration files
    Check common config locations such as the working directory, ~/.langflow, /etc/langflow, or environment variable LANGFLOW_CONFIG_PATH if set
    Affected if A configuration file exists and shows the Agentic Assistant feature is enabled or accessible
  3. Verify Agentic Assistant feature status
    Inspect configuration for 'agentic', 'assistant', or 'agent' related settings in the config file; also check if the feature endpoint is reachable by querying your Langflow instance
    Affected if The Agentic Assistant feature is enabled or exposed in the configuration
  4. Assess network exposure
    Check if Langflow server is bound to a non-localhost interface (0.0.0.0) or is accessible from external IPs; review firewall rules and reverse proxy configurations
    Affected if The Langflow service is accessible over the network without proper access controls
  5. Review running process and environment
    Examine the running Langflow process command-line arguments and environment variables for custom configurations that may enable the vulnerable feature
    Affected if The process runs with settings that enable or allow access to the Agentic Assistant functionality

You are affected if your Langflow version is below 1.9.0 AND the Agentic Assistant feature is enabled and accessible to an attacker who can influence model output.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.9.0 or later
Fixed in 1.9.0
Interim mitigation

Upgrade to Langflow version 1.9.0 or later. Until upgraded, restrict network access to the Agentic Assistant feature and disable it in untrusted deployments.

Recommended fix High confidence

Langflow 1.9.0

  1. Upgrade Langflow to version 1.9.0 or later to resolve the arbitrary server-side Python code execution vulnerability

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Langflow Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-33873 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data