CVE-2026-19298: Langflow Authorization Bypass Vulnerability

CVE-2026-19298 Overview

CVE-2026-19298 is an authorization bypass vulnerability in IBM Langflow OSS versions 1.0.0 through 1.11.2. The flaw resides in the flow build process and allows a remote authenticated attacker to execute arbitrary code on affected systems. The weakness is classified under CWE-94: Improper Control of Generation of Code. Langflow is a widely deployed low-code framework for building agentic and retrieval-augmented generation (RAG) applications, making exposed instances a high-value target for attackers seeking foothold in AI workloads.

Critical Impact
Authenticated attackers can bypass authorization controls in the flow build path to execute arbitrary code on hosts running Langflow, leading to full compromise of confidentiality, integrity, and availability.

Affected Products

Langflow OSS versions 1.0.0 through 1.11.2
Deployments on Linux, macOS, and Microsoft Windows hosts
Container and cloud-hosted Langflow instances built from vulnerable releases

Discovery Timeline

2026-09-04 - CVE-2026-19298 published to the National Vulnerability Database
2026-09-10 - Last updated in NVD database

Technical Details for CVE-2026-19298

Vulnerability Analysis

The vulnerability affects the Langflow flow build process, which compiles a user-defined graph of components into an executable pipeline. During this build step, the application fails to enforce authorization checks that should restrict which authenticated users can submit or trigger specific flow content. An attacker with any valid authenticated session can bypass these controls and cause the server to construct and evaluate attacker-supplied logic.

Because Langflow components can execute Python code and load arbitrary modules as part of a flow, an authorization bypass in the build path translates directly to remote code execution on the underlying host. The attack requires network access to the Langflow HTTP API and low privileges, with no user interaction.

Root Cause

The root cause is missing or insufficient authorization enforcement in the flow build endpoint, combined with a component model that treats built flows as trusted code. This maps to CWE-94, Improper Control of Generation of Code. Any authenticated principal, including low-privilege accounts intended only to view or run existing flows, can reach code-generating functionality reserved for privileged roles.

Attack Vector

Exploitation follows a straightforward pattern. The attacker authenticates to the Langflow instance using any valid credential, including self-registered or shared low-privilege accounts. The attacker then issues a build request containing a crafted flow definition whose components embed attacker-controlled Python logic or malicious module references. The server processes the build without validating the caller's authorization for the requested operation and executes the embedded code in the Langflow worker process.

Refer to the IBM Support Document for vendor-specific technical details and affected build metadata.

Detection Methods for CVE-2026-19298

Indicators of Compromise

Unexpected outbound network connections from the Langflow process to attacker-controlled infrastructure following a flow build request.
New or modified flow definitions containing suspicious Python components, base64-encoded payloads, or references to os, subprocess, or socket modules.
Child processes such as sh, bash, cmd.exe, or powershell.exe spawned by the Langflow application user.
Log entries showing successful /api/v1/build or equivalent flow build calls from low-privilege accounts.

Detection Strategies

Alert on process lineage where the Langflow Python interpreter spawns interactive shells, network utilities, or credential-access tools.
Correlate authentication events with flow build API calls to identify low-privilege accounts triggering build operations.
Inspect flow JSON payloads at ingest for dynamic code constructs such as exec, eval, __import__, or inline Python component overrides.

Monitoring Recommendations

Forward Langflow application, reverse proxy, and host process telemetry to a centralized analytics pipeline for correlation.
Baseline normal flow build volume per user and alert on deviations, especially bursts from newly created accounts.
Monitor egress traffic from Langflow hosts and flag connections to unrecognized domains, paste sites, or IP literals.

How to Mitigate CVE-2026-19298

Immediate Actions Required

Upgrade Langflow OSS to a fixed release beyond version 1.11.2 as identified in the vendor advisory.
Restrict network exposure of the Langflow API to trusted management networks and authenticated VPN users only.
Audit existing user accounts and revoke unused or shared low-privilege credentials that could reach the flow build endpoint.
Review recent flow definitions and build logs for signs of prior exploitation before applying the patch.

Patch Information

IBM has published remediation guidance in the IBM Support Document. Administrators should apply the vendor-supplied fixed version and validate that the upgrade covers all Langflow deployments, including container images, Helm charts, and developer instances built from source.

Workarounds

Place Langflow behind an authenticating reverse proxy that enforces additional role checks on /api/v1/build and related endpoints.
Run the Langflow process as an unprivileged OS user in an isolated container with read-only filesystem mounts and no outbound internet access.
Disable self-service account registration and require administrator approval for new Langflow users until patched.
Apply network egress filtering to block Langflow hosts from initiating arbitrary outbound connections.

bash

# Example: run Langflow in a hardened container with restricted egress
docker run -d \
  --name langflow \
  --user 10001:10001 \
  --read-only \
  --cap-drop=ALL \
  --security-opt no-new-privileges \
  --network langflow-restricted \
  -p 127.0.0.1:7860:7860 \
  langflowai/langflow:patched