{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/cve-2026-12940/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":9.8,"id":"CVE-2026-12940"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["Langflow OSS (1.0.0 - 1.10.1)"],"_cs_severities":["critical"],"_cs_tags":["remote-code-execution","cve-2026-12940","ibm","langflow","code-injection","vulnerability","rce"],"_cs_type":"advisory","_cs_vendors":["IBM"],"content_html":"\u003cp\u003eIBM Langflow OSS versions 1.0.0 through 1.10.1 contain a critical vulnerability (CVE-2026-12940) in the Model Context Protocol (MCP) stdio launcher. The flaw originates in 'src/lfx/src/lfx/base/mcp/util.py', where the 'DANGEROUS_ENV_VARS' blocklist fails to filter sensitive environment variables, specifically 'SHELLOPTS', 'BASHOPTS', and 'PS4'.\u003c/p\u003e\n\u003cp\u003eAn unauthenticated remote attacker can exploit this oversight by injecting these environment variables into the application's process execution flow. By manipulating these variables, an attacker can influence shell behavior to execute arbitrary OS commands when the launcher initiates subprocesses. Because the vulnerability allows for unauthenticated interaction with the MCP interface, it presents a significant risk for server compromise in environments hosting Langflow instances.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker identifies a target server hosting IBM Langflow OSS (versions 1.0.0 through 1.10.1).\u003c/li\u003e\n\u003cli\u003eAttacker interacts with the unauthenticated Model Context Protocol (MCP) endpoint exposed by the application.\u003c/li\u003e\n\u003cli\u003eAttacker crafts a malicious request intended to trigger the stdio launcher process.\u003c/li\u003e\n\u003cli\u003eAttacker injects forbidden environment variables ('SHELLOPTS', 'BASHOPTS', or 'PS4') into the application's request parameters.\u003c/li\u003e\n\u003cli\u003eThe 'DANGEROUS_ENV_VARS' blocklist in the vulnerable 'util.py' script fails to filter the injected variables.\u003c/li\u003e\n\u003cli\u003eThe application initializes a subprocess using the influenced environment settings.\u003c/li\u003e\n\u003cli\u003eThe shell interpreter executes arbitrary commands defined via the injected variables, resulting in remote code execution.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of this vulnerability leads to unauthenticated remote code execution on the underlying host. This grants an attacker the ability to execute arbitrary commands, potentially leading to total system compromise, data exfiltration, or deployment of further payloads. Given the nature of the application as an orchestration tool for AI workflows, attackers could potentially manipulate sensitive LLM inputs or access internal network resources from the compromised container or host.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eImmediately upgrade IBM Langflow OSS to a patched version beyond 1.10.1 to mitigate CVE-2026-12940.\u003c/li\u003e\n\u003cli\u003eReview logs for unusual process spawning activities originating from the Langflow process user.\u003c/li\u003e\n\u003cli\u003eRestrict network access to the Langflow MCP management interface to trusted internal segments only, as the vulnerability does not require authentication.\u003c/li\u003e\n\u003cli\u003eImplement strict environment variable monitoring and container security policies to detect attempts to inject shell-specific variables into application subprocesses.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-07-30T19:30:32Z","date_published":"2026-07-30T17:29:49Z","id":"https://feed.craftedsignal.io/briefs/2026-07-langflow-rce/","summary":"IBM Langflow OSS versions 1.0.0 through 1.10.1 are susceptible to unauthenticated remote code execution due to improper sanitization of environment variables in the MCP stdio launcher.","title":"Unauthenticated Remote Code Execution in IBM Langflow OSS","url":"https://feed.craftedsignal.io/briefs/2026-07-langflow-rce/"}],"language":"en","title":"CraftedSignal Threat Feed - Cve-2026-12940","version":"https://jsonfeed.org/version/1.1"}