Security Digest · Vulnerability record
CVE-2026-27966: Langflow has Remote Code Execution in CSV Agent
Langflow is a tool for building and deploying AI-powered agents and workflows.
CVSS 9.8 Critical EPSS 2.5% · p85
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 2.5%, percentile 85: FIRST’s model estimates a 2.5% chance of exploitation activity in the next 30 days, higher than 85% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
langflow(PyPI) <= 1.8.0rc2, no fixed version listed. Check your lockfile, including transitive dependencies.
What it is
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.8.0, 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). Version 1.8.0 fixes the issue.
From the GitHub advisory
1. 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).
2. 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.
Weakness type: CWE-94.
Product: langflow (PyPI) · Assigned by: GitHub_M · Published: 2026-02-26
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | langflow | <= 1.8.0rc2 | none listed |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| langflow-ai | langflow | < 1.8.0 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 2.55% probability of exploitation activity in the next 30 days; percentile 85.
Timeline
- — CVE record published by GitHub_M
- — GitHub-reviewed advisory GHSA-3645-fxcv-hqr4 published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-3645-fxcv-hqr4 github.com
- CVE.org record CVE-2026-27966 cve.org
- NVD entry CVE-2026-27966 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com