CVE-2026-27966 is a critical-severity code injection vulnerability in langflow (pip), affecting versions <= 1.8.0rc2. No fixed version is listed yet.
Summary The CSV Agent node in Langflow hardcodes allowdangerouscode=True, which automatically exposes LangChain’s Python REPL tool (pythonreplast). As a result, an attacker can execute arbitrary Python and OS commands on the server via prompt injection, leading to full Remote Code Execution (RCE). Description 2.1 Intended Functionality When building a flow such as ChatInput → CSVAgent → ChatOutput, users can attach an LLM and specify a CSV file path. The CSV Agent then provides capabilities to query, summarize, or manipulate the CSV content using an LLM-driven agent. 2.2 Root Cause In src/lfx/src/lfx/components/langchainutilities/csvagent.py, the CSV Agent is instantiated as follows: Because allowdangerouscode is hardcoded to True, LangChain automatically enables the pythonreplast tool. Any LLM output that issues an action such as: is executed directly on the server. There is no UI toggle or environment variable to disable this behavior. Proof of Concept (PoC) Create a flow: ChatInput → CSVAgent → ChatOutput. Provide a CSV path (e.g., /tmp/poc.csv) and attach an LLM. Send the following prompt: After execution, the file /tmp/pwned is created on the server → RCE confirmed. Impact Remote attackers can execute arbitrary Python code and system commands on the Langflow server. Full takeover of the server environment is possible. No configuration option currently exists to disable this behavior. Patch Recommendation Set allowdangerouscode=False by default, or remove the parameter entirely to prevent automatic inclusion of the Python REPL tool. If the feature is required, expose a UI toggle with Default: False.
Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.
CVE-2026-27966 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
pip
langflow (<= 1.8.0rc2)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's Application Detection and Response identifies whether CVE-2026-27966 is reachable in your applications. Explore runtime application protection for your team.
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No fixed version is listed for CVE-2026-27966 yet.
In the interim: Never evaluate untrusted input as code. Use sandboxed evaluation environments if dynamic execution is required.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-27966 is a critical-severity code injection vulnerability in langflow (pip), affecting versions <= 1.8.0rc2. No fixed version is listed yet. Untrusted input is evaluated as executable code within the application's runtime environment.
CVE-2026-27966 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
langflow (pip) versions <= 1.8.0rc2 is affected.
No fixed version is listed for CVE-2026-27966 yet. Monitor the advisory for updates and apply mitigations in the interim.
Whether CVE-2026-27966 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
No fixed version is listed yet. In the interim: Never evaluate untrusted input as code. Use sandboxed evaluation environments if dynamic execution is required.