CVE-2026-12940: 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

criticalCVSS 9.8CVE-2026-12940

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.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: critical — CVSS 9.8
Published: 2026-07-30
Last updated: 2026-07-31
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-12940

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-129400.48% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 39% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-12940	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[NEW] [high] IBM Langflow Desktop: Multiple vulnerabilitiescert-bund

Recent advisories for IBM Langflow OSS

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

medium[NEW] [medium] IBM Langflow Desktop OSS: Vulnerability allows information disclosurecert-bund · 2026-07-31
criticalCVE-2026-12946: IBM Langflow OSS 1.0.0 through 1.10.0 could allow a remote attacker to inject arbitrary code o…nvd · 2026-07-30
highCVE-2026-13444: IBM Langflow OSS 1.0.0 through 1.10.1 can allow an attacker to access another user's private v…nvd · 2026-07-30
criticalCVE-2026-13435: IBM Langflow OSS 1.0.0 through 1.10.1 contains an improper input validation vulnerability in t…nvd · 2026-07-30
highCVE-2026-12942: IBM Langflow OSS 1.0.0 through 1.10.1 could allow a remote attacker to traverse directories on…nvd · 2026-07-30
mediumCVE-2026-10700: IBM Langflow OSS 1.0.0 through 1.8.4 contains multiple broken access control vulnerabilities i…nvd · 2026-07-30