CVE-2026-9198: Langflow token forgery + exec()

CISO Take

Langflow's /api/v1/auto_login endpoint mints a valid SUPERUSER JWT for any unauthenticated network caller, and that token can immediately be used against /api/v1/validate/code, an endpoint that runs submitted Python through exec(). Chained together, a remote attacker with zero credentials and zero user interaction gets full code execution on any default Langflow deployment — this is as close to a worst-case CVSS 9.8 as it gets for an agent-orchestration framework. There is no EPSS score or CISA KEV listing yet and no public PoC or Nuclei template has surfaced, but the bug requires no exploitation skill (two chained HTTP calls) and Langflow already carries 69 other CVEs and a package risk score of 77/100, so mass scanning the moment this becomes public is a near-certainty. Patch to the fixed IBM Langflow release immediately, and until confirmed patched, do not expose Langflow's API on any untrusted network — put it behind authentication at the network layer (VPN/mTLS/allowlist) since the app's own auth cannot be trusted for this endpoint pair. Detection teams should alert on any external call to /api/v1/auto_login followed by /api/v1/validate/code, and hunt for unexpected child processes spawned by the Langflow service account.

Sources: NVD ibm.com ATLAS

What is the risk?

Critical risk. CVSS 3.1 base score 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) reflects an unauthenticated, no-interaction, low-complexity path to full compromise. The combination of an auth-bypass primitive (forged SUPERUSER token) and a code-execution primitive (exec() over untrusted input) in the same default install removes essentially every barrier an attacker would otherwise need to clear. No EPSS score, KEV listing, public exploit, or scanner template exists yet, which caps immediate mass-exploitation confidence at MEDIUM, but the low skill bar and the framework's track record (69 prior CVEs, risk score 77/100) make rapid weaponization likely once details circulate.

How does the attack unfold?

Discovery

Attacker scans the internet for exposed Langflow instances running the default, unpatched configuration.

AML.T0006

Authentication Bypass

Attacker calls the unauthenticated /api/v1/auto_login endpoint, which mints a valid SUPERUSER token for any caller.

AML.T0012

Code Execution

Using the forged SUPERUSER token, the attacker submits Python code to /api/v1/validate/code, which runs it via exec().

AML.T0050

Impact

The attacker achieves full remote code execution on the Langflow host, exposing connected credentials, data, and any linked AI tooling.

AML.T0112

Discovery

Attacker scans the internet for exposed Langflow instances running the default, unpatched configuration.

AML.T0006

Authentication Bypass

Attacker calls the unauthenticated /api/v1/auto_login endpoint, which mints a valid SUPERUSER token for any caller.

AML.T0012

Code Execution

Using the forged SUPERUSER token, the attacker submits Python code to /api/v1/validate/code, which runs it via exec().

AML.T0050

Impact

The attacker achieves full remote code execution on the Langflow host, exposing connected credentials, data, and any linked AI tooling.

AML.T0112

What systems are affected?

Package	Ecosystem	Vulnerable Range	Patched
Langflow	pip	—	No patch
153.9K Pushed yesterday 20% patched ~70d to patch Full package profile →

Do you use Langflow? You're affected.

How severe is it?

CVSS 3.1

9.8 / 10

EPSS

34.7%

chance of exploitation in 30 days

Higher than 98% of all CVEs

Source: EPSS v3 — FIRST.org

Exploitation Status

Actively Exploited

CISA KEV

Sophistication

Trivial

Exploitation Confidence

high

✓ CISA KEV (active exploitation confirmed) — Aug 2026

✓ CISA SSVC: Active exploitation

✓ Weaponized Metasploit module (exploit/multi/http/langflow_unauth_rce_cve_2026_9198)

○ Nuclei detection template available

○ EPSS exploit prediction: 35%

Composite signal derived from CISA KEV, VulnCheck KEV, CISA SSVC, EPSS, Metasploit, Exploit-DB, trickest/cve, Nuclei templates, and inthewild.io exploitation reports.

What is the attack surface?

AV Network

AC Low

PR None

UI None

S Unchanged

C High

I High

A High

What should I do?

1 step

1) Patch to the IBM-fixed Langflow release immediately (see vendor advisory) — do not wait for a documented CVE range if a newer release is available. 2) Until patched, never expose the Langflow API directly to the internet or untrusted networks; place it behind a VPN, mTLS, or IP allowlist, since the vulnerability lives inside the app's own auth logic. 3) Rotate any credentials/API keys accessible from the Langflow host, since a prior compromise may already have occurred. 4) Detection: alert on unauthenticated or anomalous calls to /api/v1/auto_login, especially followed by calls to /api/v1/validate/code from the same session/token; monitor for unexpected subprocess spawning or outbound connections from the Langflow service process. 5) Restrict the service account running Langflow to least privilege so exec()-based compromise has a smaller blast radius.

What does CISA's SSVC say?

Decision Act

Exploitation active

Automatable Yes

Technical Impact total

Source: CISA Vulnrichment (SSVC v2.0). Decision based on the CISA Coordinator decision tree.

How is it classified?

Auth Bypass Code Execution Framework Agent AML.T0012 - Valid Accounts AML.T0049 - Exploit Public-Facing Application AML.T0050 - Command and Scripting Interpreter AML.T0112 - Machine Compromise

Which compliance frameworks are affected?

This CVE is relevant to:

EU AI Act

Article 15 - Accuracy, Robustness and Cybersecurity

NIST AI RMF

MEASURE 2.7 - AI system security and resilience are evaluated and documented

OWASP LLM Top 10

LLM06 - Excessive Agency

Frequently Asked Questions

What is CVE-2026-9198?

Langflow's /api/v1/auto_login endpoint mints a valid SUPERUSER JWT for any unauthenticated network caller, and that token can immediately be used against /api/v1/validate/code, an endpoint that runs submitted Python through exec(). Chained together, a remote attacker with zero credentials and zero user interaction gets full code execution on any default Langflow deployment — this is as close to a worst-case CVSS 9.8 as it gets for an agent-orchestration framework. There is no EPSS score or CISA KEV listing yet and no public PoC or Nuclei template has surfaced, but the bug requires no exploitation skill (two chained HTTP calls) and Langflow already carries 69 other CVEs and a package risk score of 77/100, so mass scanning the moment this becomes public is a near-certainty. Patch to the fixed IBM Langflow release immediately, and until confirmed patched, do not expose Langflow's API on any untrusted network — put it behind authentication at the network layer (VPN/mTLS/allowlist) since the app's own auth cannot be trusted for this endpoint pair. Detection teams should alert on any external call to /api/v1/auto_login followed by /api/v1/validate/code, and hunt for unexpected child processes spawned by the Langflow service account.

Is CVE-2026-9198 actively exploited?

Yes, CVE-2026-9198 is confirmed actively exploited and listed in CISA Known Exploited Vulnerabilities catalog since Tue Aug 04 2026 00:00:00 GMT+0000 (Coordinated Universal Time).

How to fix CVE-2026-9198?

1) Patch to the IBM-fixed Langflow release immediately (see vendor advisory) — do not wait for a documented CVE range if a newer release is available. 2) Until patched, never expose the Langflow API directly to the internet or untrusted networks; place it behind a VPN, mTLS, or IP allowlist, since the vulnerability lives inside the app's own auth logic. 3) Rotate any credentials/API keys accessible from the Langflow host, since a prior compromise may already have occurred. 4) Detection: alert on unauthenticated or anomalous calls to /api/v1/auto_login, especially followed by calls to /api/v1/validate/code from the same session/token; monitor for unexpected subprocess spawning or outbound connections from the Langflow service process. 5) Restrict the service account running Langflow to least privilege so exec()-based compromise has a smaller blast radius.

What systems are affected by CVE-2026-9198?

This vulnerability affects the following AI/ML architecture patterns: agent frameworks, LLM orchestration pipelines, RAG pipelines, internal AI dev/ops platforms.

What is the CVSS score for CVE-2026-9198?

CVE-2026-9198 has a CVSS v3.1 base score of 9.8 (CRITICAL). The EPSS exploitation probability is 34.73%.

What is the AI security impact?

Affected AI Architectures

agent frameworksLLM orchestration pipelinesRAG pipelinesinternal AI dev/ops platforms

MITRE ATLAS Techniques

AML.T0012 Valid Accounts

AML.T0049 Exploit Public-Facing Application

AML.T0050 Command and Scripting Interpreter

AML.T0112 Machine Compromise

Compliance Controls Affected

EU AI Act: Article 15

NIST AI RMF: MEASURE 2.7

OWASP LLM Top 10: LLM06

What are the technical details?

Original Advisory

IBM Langflow OSS 1.0.0 through 1.10.0 allows unauthenticated attackers to chain /api/v1/auto_login (mints SUPERUSER tokens to any network caller) with /api/v1/validate/code (executes user code via exec()) to achieve full RCE on default Langflow deployments

Exploitation Scenario

An attacker scans the internet for exposed Langflow instances (default ports/paths are well known). Against a target instance, they send an unauthenticated request to /api/v1/auto_login, which returns a valid SUPERUSER JWT with no credentials required. Using that token, the attacker calls /api/v1/validate/code with a payload containing arbitrary Python (e.g., a reverse shell or credential-harvesting script), which the endpoint executes server-side via exec(). The attacker now has a shell on the host, can exfiltrate any LLM API keys, vector DB credentials, or connected tool secrets configured in Langflow flows, and can pivot further into the internal network.

Weaknesses (CWE)

CWE-94 Improper Control of Generation of Code ('Code Injection') Primary CWE-94 Improper Control of Generation of Code ('Code Injection')

CWE-94 — 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.

[Architecture and Design] Refactor your program so that you do not have to dynamically generate code.
[Architecture and Design] Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.

Source: MITRE CWE corpus.