CVE-2026-12940(langflow / langflow)

LOWCVSS 9.8 · CRITICAL

Immediate actions

Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

IBM Langflow OSS 1.0.0 through 1.10.1 are vulnerable to unauthenticated remote code execution via environment variable injection in the MCP (Model Context Protocol) stdio launcher. The vulnerability exists in src/lfx/src/lfx/base/mcp/util.py where the DANGEROUS_ENV_VARS blocklist fails to include SHELLOPTS , BASHOPTS , and PS4 environment variables.

langflow CVEs Back to dashboard

0.0/ 10 priority

Sources & remediation

Vendor / third-party advisories

https://www.ibm.com/support/pages/node/7279995

Weakness type (CWE)

CWE-78

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

NONE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

langflow

Affected systems

Vendors

langflow

Products

langflow

Deep dive

Full discourse5 posts

ThreatWire@ThreatWire_43d
PoC
🚨 A public PoC has been released for CVE-2026-12940 affecting IBM Langflow OSS. The vulnerability allows unauthenticated RCE via environment variable injection in the MCP stdio launcher. 🔗 https://github.com/biitts/cve-2026-12940-langflow-unauth-rce #Langflow #RCE #CVE #CyberSecurity
Post summary
A public proof of concept for CVE-2026-12940 has been released, detailing an unauthenticated RCE via environment variable injection in IBM Langflow OSS, but no active exploitation or patch information is provided.
013030151.9K
1.0K followersView on X
dbugs@ptdbugs43d
PoC
A PoC/exploit has been discovered for vulnerability CVE-2026-12940 PT ID: PT-2026-66519 Vendor: IBM Product: Langflow OSS Description: IBM Langflow OSS 1.0.0 through 1.10.1 are vulnerable to unauthenticated remote code execution via environment variable injection in the MCP (Model Context Protocol) stdio launcher. The vulnerability exists in src/lfx/src/lfx/base/mcp/util.py where the DANGEROUS_ENV_VARS blocklist fails to include SHELLOPTS , BASHOPTS , and PS4 environment variables. References: • https://dbugs.ptsecurity.com/vulnerability/PT-2026-66519 • https://github.com/biitts/cve-2026-12940-langflow-unauth-rce #dbugs_vuln
Post summary
A Proof of Concept for CVE-2026-12940 has been discovered and shared, demonstrating unauthenticated remote code execution via environment variable injection in IBM Langflow OSS. No active exploitation or patch information is provided.
00033735
3.4K followersView on X
DFIR Lab@DFIR_Lab46d
Patch
🚨 CRITICAL: CVE-2026-12940 (CVSS 9.8) IBM Langflow OSS 1.0.0-1.10.1 vulnerable to unauthenticated RCE via environment variable injection in MCP stdio launcher. No authentication required. Patch immediately. #CVE #PatchNow #ThreatIntel https://t.co/yCgMrVdr28
Post summary
Critical unauthenticated RCE disclosed for IBM Langflow OSS; a patch is urgently recommended to address the high‑severity vulnerability.
0001049
99 followersView on X
IntegSec@integ_sec7d
General
CVE-2026-12940: IBM Langflow OSS Unauthenticated Remote Code Execution via Environment Variable Injection - What It Means for Your Business and How to Respond https://hubs.li/Q04wZLVh0
Post summary
The text highlights the nature of CVE-2026-12940 and suggests business impact and response strategies, but lacks details on exploits, patches, or active use.
0000035
35 followersView on X
Hephaestvs@Vulcanux_40d
PoC
csirt_it: ‼️ #PoC #IBM: disponibile Proof of Concept (PoC) per la CVE-2026-12940 in #LangFlow #OSS Rischio: 🟠 Tipologia: 🔸 Remote Code Execution 🔗 https://www.acn.gov.it/portale/w/langflow-poc-pubblico-per-lo-sfruttamento-della-cve-2026-12940 ⚠️ Importante mantenere aggiornati i sistemi https://t.co/1rZzhsiWJq
Post summary
The post announces a publicly available Proof of Concept for CVE-2026-12940, highlighting its Remote Code Execution nature and advising users to keep systems updated.
0000052
628 followersView on X

CPE platform detail1 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

1 of 1 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	langflow	langflow	-	-	-

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What researchers are saying

CVE-2026-12940

ThreatWire[verified]@ThreatWire_PoC

A public proof of concept for CVE-2026-12940 has been released, detailing an unauthenticated RCE via environment variable injection in IBM Langflow OSS, but no active exploitation or patch information is provided.

dbugs[verified]@ptdbugsPoC

A Proof of Concept for CVE-2026-12940 has been discovered and shared, demonstrating unauthenticated remote code execution via environment variable injection in IBM Langflow OSS. No active exploitation or patch information is provided.

DFIR Lab[verified]@DFIR_LabPatch

Critical unauthenticated RCE disclosed for IBM Langflow OSS; a patch is urgently recommended to address the high‑severity vulnerability.

IntegSec[verified]@integ_secGeneral

The text highlights the nature of CVE-2026-12940 and suggests business impact and response strategies, but lacks details on exploits, patches, or active use.

Hephaestvs@Vulcanux_PoC

The post announces a publicly available Proof of Concept for CVE-2026-12940, highlighting its Remote Code Execution nature and advising users to keep systems updated.