CVE-2026-12940criticalCWE-78

CVE-2026-12940: critical vulnerability in IBM Langflow OSS

Langflow is affected by remote code execution due to multiple unauthenticated and insufficiently authorized API endpoints

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48Vexday Risk Score

No sign of exploitation. It has a public proof of concept.

ssvc Attendcvss 9.8epss 0.9%
from disclosure to weapon4 days
Published on NVDJul 30
1st PoC+4d
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
IBM · Langflow OSS
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
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