Langflow auto_login + validate/code Chain Unauthenticated RCE (CVE-2026-9198) (Direct Check)

critical Nessus Plugin ID 334529

Synopsis

The remote host is running a web application affected by multiple vulnerabilities that can be chained for unauthenticated remote code execution.

Description

The version of Langflow running on the remote host is affected by two vulnerabilities that can be chained to achieve unauthenticated remote code execution:

- CVE-2026-9103: The '/api/v1/auto_login' endpoint mints a superuser JWT bearer token to any unauthenticated caller when the default AUTO_LOGIN configuration is enabled.

- CVE-2026-8481: The '/api/v1/validate/code' endpoint compiles and evaluates attacker-supplied Python during 'validation' using an unsandboxed exec() whose globals expose importlib and Python builtins. Function default-argument values and decorators are executed at definition time.

A remote, unauthenticated attacker can chain these flaws by first requesting a superuser token from the auto_login endpoint, then submitting crafted Python code to validate/code whose default argument executes arbitrary Python, and ultimately arbitrary operating system commands, as the Langflow service user.

Nessus confirmed the chain non-destructively by obtaining a token from /auto_login and coercing the target into performing an out-of-band callback (a DNS lookup and/or a direct socket connection) back to the Nessus scanner. No operating system commands were executed on the target.

Solution

Upgrade to Langflow version 1.10.1 or later.

See Also

https://github.com/advisories/GHSA-5wm9-vgmg-cjv6

Plugin Details

Severity: Critical

ID: 334529

File Name: langflow_auto_login_validate_code_rce_cve_2026_9198.nbin

Version: 1.1

Type: Remote

Published: 8/11/2026

Updated: 8/11/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 9.2

Percentile: 99.76

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vulnerability Information

CPE: cpe:/a:langflow:langflow

Required KB Items: installed_sw/Langflow

Exploit Available: true

Exploit Ease: Exploits are available

Exploited by Nessus: true

Patch Publication Date: 7/29/2026

Vulnerability Publication Date: 7/17/2026

Reference Information

CVE: CVE-2026-8481, CVE-2026-9103, CVE-2026-9198