CVE-2026-12944: IBM Langflow OSS RCE Vulnerability

CVE-2026-12944 Overview

CVE-2026-12944 is a server-side request forgery and code execution flaw in IBM Langflow OSS versions 1.0.0 through 1.10.0. Attackers can execute arbitrary Python code as root (UID=0) on the Langflow server by submitting components that contain socket or urllib imports. The component scanner incorrectly returns "validated": true, providing a false security signal to operators. Exploitation enables Amazon Web Services (AWS) credential theft through Instance Metadata Service version 1 (IMDSv1) SSRF, arbitrary file exfiltration from the container filesystem, and lateral movement to internal services such as PostgreSQL and Redis on the Docker network. The weakness is tracked under CWE-918: Server-Side Request Forgery.

Critical Impact
Authenticated attackers gain root-level Python execution on the Langflow host, enabling cloud credential theft, data exfiltration, and lateral movement into backend services.

Affected Products

IBM Langflow OSS 1.0.0
IBM Langflow OSS versions between 1.0.0 and 1.10.0
IBM Langflow OSS 1.10.0

Discovery Timeline

2026-09-14 - CVE-2026-12944 published to the National Vulnerability Database
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-12944

Vulnerability Analysis

IBM Langflow OSS accepts user-supplied components that are evaluated by the server as Python code. The platform ships with a scanner intended to reject components performing sensitive operations such as network calls. The scanner fails to detect submissions that import socket or urllib, and it returns "validated": true for these malicious components. The Langflow worker process runs as root inside its container, so any code path reached through this bypass executes with UID 0.

Once loaded, an attacker-controlled component can open outbound sockets and issue HTTP requests from the server. This turns the Langflow instance into a proxy for internal network access. Because the container in typical deployments has network reachability to the AWS metadata endpoint, PostgreSQL, and Redis, a single request can pivot from application-level access to infrastructure compromise.

Root Cause

The root cause is incomplete input validation in the component scanner. The scanner enumerates a denylist of dangerous imports but omits socket and urllib. The scanner also fails closed on a positive validation result, meaning downstream logic trusts the validated flag without secondary sandboxing. Combined with the container running as root, the bypass yields full code execution rather than a restricted sandbox escape.

Attack Vector

The attack requires only low-privilege authenticated access to the Langflow application. An attacker submits a component containing import socket or import urllib alongside logic that fetches AWS credentials from http://169.254.169.254/latest/meta-data/iam/security-credentials/, reads local files such as /etc/shadow or .env configuration, or opens TCP connections to internal service ports. The scanner accepts the component, the worker executes it, and the response returns exfiltrated data to the attacker.

No verified proof-of-concept code has been published. Refer to the IBM Support Page for vendor technical details.

Detection Methods for CVE-2026-12944

Indicators of Compromise

Outbound HTTP requests from the Langflow container to 169.254.169.254, the AWS Instance Metadata Service endpoint.
Langflow component submissions containing import socket, import urllib, urllib.request, or http.client in payload bodies.
Unexpected TCP connections from the Langflow container to PostgreSQL (5432), Redis (6379), or other internal service ports.
Reads of sensitive filesystem paths such as /proc/self/environ, /etc/shadow, or application .env files by the Langflow process.

Detection Strategies

Inspect Langflow API request bodies for component definitions containing networking or filesystem imports before they reach the scanner.
Correlate the scanner's "validated": true responses with subsequent outbound connections initiated by the same worker process.
Alert on any egress from Langflow containers to link-local metadata addresses or RFC1918 ranges outside the expected service mesh.

Monitoring Recommendations

Enable container runtime telemetry (process, file, and network events) for all Langflow workloads and forward events to a central analytics platform.
Monitor AWS CloudTrail for AssumeRole and GetSessionToken events tied to the Langflow instance profile that originate from unexpected source IPs.
Track authentication logs for Langflow accounts that submit components at abnormal frequency or from new geographies.

How to Mitigate CVE-2026-12944

Immediate Actions Required

Upgrade IBM Langflow OSS to a version above 1.10.0 that addresses the scanner bypass, per the IBM Support Page.
Disable IMDSv1 on the underlying EC2 instances and enforce Instance Metadata Service version 2 (IMDSv2) with hop limit 1.
Rotate any AWS credentials, database passwords, and API keys accessible from the Langflow container.
Restrict access to the Langflow web interface to trusted administrators and remove default or shared accounts.

Patch Information

IBM has published guidance on the IBM Support Page. Apply the vendor-provided fixed release for Langflow OSS and validate that the component scanner rejects submissions containing socket and urllib imports after upgrade.

Workarounds

Run the Langflow container as a non-root user and apply a read-only root filesystem with a seccomp profile that blocks socket() syscalls where feasible.
Enforce a Kubernetes NetworkPolicy or Docker network rule that blocks egress from Langflow pods to 169.254.169.254/32 and to internal database subnets.
Place Langflow behind an authenticating reverse proxy and disable public exposure of the component submission API.
Require code review or an allow-list workflow for all custom components before they can be executed by the runtime.

bash

# Example: block AWS metadata access from Langflow containers using iptables
iptables -I OUTPUT -m owner --uid-owner langflow \
  -d 169.254.169.254 -j DROP

# Example: enforce IMDSv2 on the underlying EC2 instance
aws ec2 modify-instance-metadata-options \
  --instance-id i-0123456789abcdef0 \
  --http-tokens required \
  --http-put-response-hop-limit 1 \
  --http-endpoint enabled