# Unauthenticated Remote Code Execution in Langflow via Public Flow Build Endpoint

Advisory record · `GHSA-vwmf-pq79-vjvx`

- **Identifiers:** `GHSA-vwmf-pq79-vjvx` · `CVE-2026-33017` · `PYSEC-2026-379`
- **State:** Confirmed
- **Severity:** CVSS 9.3 Critical
- **Critical:** Yes: KEV, CVSS 9+, CVSS 7+ and EPSS
- **Weakness (CWE):** [CWE-94](https://cwe.mitre.org/data/definitions/94.html) · [CWE-95](https://cwe.mitre.org/data/definitions/95.html) · [CWE-306](https://cwe.mitre.org/data/definitions/306.html)
- **Tags:** [Code injection](https://agentprime.io/advisories/tag/code-injection.md) · [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md)
- **Published:** 29 Jun 2026
- **Updated:** 13 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 29 Jun 2026, 11:50 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Critical

Critical, because:

- In CISA’s KEV catalogue since 25 Mar 2026: it is known to be exploited.
- CVSS score 9.3: 9.0 or more.
- CVSS score 9.3 (7.0 or more) and EPSS 0.96 (0.1 or more): a high score and a real chance of exploitation in the next 30 days.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected packages

- `langflow` (PyPI): affected `<1.9.0`; fixed in `1.9.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Langflow versions before 1.9.0 are affected. The POST /api/v1/build_public_tmp/{flow_id}/flow endpoint accepts attacker-supplied flow data for public flows without authentication, and that data can contain Python code that the server executes. An unauthenticated attacker who knows a public flow's ID could run arbitrary code with the server process's privileges. Upgrade to Langflow 1.9.0 or later.

Written 6 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 9.3 Critical, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L`, from CNA (GitHub_M)

- **CISA KEV:** Listed since 25 Mar 2026: known to be exploited.
- **EPSS:** 0.96, the 99th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 15:04 UTC: First seen by agentprime
- 31 Oct 2026, 15:04 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/PYSEC-2026-379)

## Sources

- [GitHub Advisory Database: GHSA-vwmf-pq79-vjvx](https://github.com/advisories/GHSA-vwmf-pq79-vjvx)
- [OSV: GHSA-vwmf-pq79-vjvx](https://osv.dev/vulnerability/GHSA-vwmf-pq79-vjvx)
- <https://github.com/langflow-ai/langflow/security/advisories/GHSA-vwmf-pq79-vjvx>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-33017>
- <https://github.com/langflow-ai/langflow/issues/12345>
- <https://github.com/langflow-ai/langflow/pull/12160>
- <https://github.com/langflow-ai/langflow/commit/73b6612e3ef25fdae0a752d75b0fabd47328d4f0>
- <https://github.com/advisories/GHSA-rvqx-wpfh-mfx7>
- <https://github.com/langflow-ai/langflow>
- <https://github.com/langflow-ai/langflow/releases/tag/1.8.2>
- <https://medium.com/@aviral23/cve-2026-33017-how-i-found-an-unauthenticated-rce-in-langflow-by-reading-the-code-they-already-dc96cdce5896>
- <https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-33017>
- <https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-33017>
- <https://www.sysdig.com/blog/cve-2026-33017-how-attackers-compromised-langflow-ai-pipelines-in-20-hours>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-vwmf-pq79-vjvx>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-vwmf-pq79-vjvx/>. Everything for agents: <https://agentprime.io/llms.txt>.