CVE-2026-33017

Langflow Langflow — Langflow Code Injection Vulnerability

criticalActively exploitedPoCEPSS 100%
Severity
critical
Priority score
228.34
KEV status
Actively exploited
Exploit maturity
actively exploited (KEV)
CVSS v3
—
CVSS v4
9.3
EPSS percentile
99.9 %
Critical — model predicts very high exploitation likelihood in the next 30 days.
Published
2026-03-25 00:00 UTC
CWE
CWE-94, CWE-95, CWE-306

Weakness classes (CWE)

  • CWE-94Base

    Improper Control of Generation of Code ('Code Injection')

    The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

    cwe.mitre.org →

  • CWE-95Variant

    Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')

    The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. "eval").

    cwe.mitre.org →

  • CWE-306Base

    Missing Authentication for Critical Function

    The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

    cwe.mitre.org →

Description

Langflow is a tool for building and deploying AI-powered agents and workflows. In versions prior to 1.9.0, the POST /api/v1/build_public_tmp/{flow_id}/flow endpoint allows building public flows without requiring authentication. When the optional data parameter is supplied, the endpoint uses attacker-controlled flow data (containing arbitrary Python code in node definitions) instead of the stored flow data from the database. This code is passed to exec() with zero sandboxing, resulting in unauthenticated remote code execution. This is distinct from CVE-2025-3248, which fixed /api/v1/validate/code by adding authentication. The build_public_tmp endpoint is designed to be unauthenticated (for public flows) but incorrectly accepts attacker-supplied flow data containing arbitrary executable code. This issue has been fixed in version 1.9.0.

Source: CISA_KEV

Public exploit references

Public proof-of-concepts and detection templates for this vulnerability. Maturity ranges from reported PoCs through working detection scripts up to fully weaponized exploit modules. NEOSEC mirrors the code internally for forensic analysis; externally we only link to the original sources.

References & sources