---
title: "CVE-2026-33873: Langflow has Authenticated Code Execution in Agentic Assistant Validation"
url: https://erroneo.us/security/cve/CVE-2026-33873/
description: "CVE-2026-33873 (langflow (PyPI)): Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.9.0, the Agentic…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-27
date_modified: 2026-06-06
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-33873"
kev: false
cvss: 9.3
epss: 0.01816
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-33873: Langflow has Authenticated Code Execution in Agentic Assistant Validation

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.8% , percentile 78: FIRST’s model estimates a 1.8% chance of exploitation activity in the next 30 days, higher than 78% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes langflow (PyPI) <= 1.8.1, fixed in 1.9.0 . 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 1.9.0, the Agentic Assistant feature in Langflow executes LLM-generated Python code during its validation phase. Although this phase appears intended to validate generated component code, the implementation reaches dynamic execution sinks and instantiates the generated class server-side. In deployments where an attacker can access the Agentic Assistant feature and influence the model output, this can result in arbitrary server-side Python execution. Version 1.9.0 fixes the issue.

## Affected packages

- PyPI `langflow` <= 1.8.1 → fixed: 1.9.0

## Affected products (CVE record)

- langflow-ai langflow: < 1.9.0

## Severity

- GitHub_M CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.82% probability of exploitation activity in the next 30 days; percentile 78.

## Sources

- [GitHub Advisory GHSA-v8hw-mh8c-jxfc](https://github.com/advisories/GHSA-v8hw-mh8c-jxfc)
- [CVE.org record CVE-2026-33873](https://www.cve.org/CVERecord?id=CVE-2026-33873)
- [NVD entry CVE-2026-33873](https://nvd.nist.gov/vuln/detail/CVE-2026-33873)
- [github.com](https://github.com/langflow-ai/langflow/security/advisories/GHSA-v8hw-mh8c-jxfc)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/api/router.py#L252-L297)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/api/schemas.py#L20-L31)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/helpers/code_extraction.py#L11-L53)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/helpers/validation.py#L27-L47)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/services/assistant_service.py#L142-L156)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/services/assistant_service.py#L259-L300)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/services/assistant_service.py#L58-L79)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/api/utils/core.py#L38)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/api/v1/login.py#L96-L135)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/services/auth/utils.py#L156-L163)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/services/auth/utils.py#L39-L53)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/lfx/src/lfx/custom/validate.py#L241-L272)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/lfx/src/lfx/custom/validate.py#L394-L399)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/lfx/src/lfx/custom/validate.py#L441-L443)
- [github.com](https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/lfx/src/lfx/services/settings/auth.py#L71-L87)
- [github.com](https://github.com/pypa/advisory-database/tree/main/vulns/langflow/PYSEC-2026-82.yaml)

---
Source page: https://erroneo.us/security/cve/CVE-2026-33873/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt