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9.4

Langflow lets any logged-in user access all flows

CVE-2026-34046 · published 7 months ago
Summary

In versions before 1.5.1, Langflow did not verify that a logged‑in user owned a flow before showing, changing, or deleting it. This means a user could see or alter another person’s AI workflow and any embedded secrets. Upgrade to version 1.5.1 or later, which adds the necessary ownership check.

What to do
  • Update carlos coelho langflow to version 1.5.1.
  • Update carlos coelho langflow-base to version 0.5.1.
  • Update langflow langflow to version 1.5.0 or later.
  • Update langflow langflow-base to version 0.5.1 or later.
Affected software
Ecosystem VendorProductAffected versions
pip carlos coelho langflow <= 1.5.0
Fix: upgrade to 1.5.1
pip carlos coelho langflow-base <= 0.5.0
Fix: upgrade to 0.5.1
PyPI carlos coelho langflow-base < 0.5.1
Fix: upgrade to 0.5.1
PyPI carlos coelho langflow < 1.5.1
Fix: upgrade to 1.5.1
– langflow langflow 1.5.0
< 1.5.0
1.5.1
cpe:2.3:a:langflow:langflow:1.5.0:dev4:*:*:*:*:*:*
– langflow langflow-base < 0.5.1
cpe:2.3:a:langflow:langflow-base:*:*:*:*:*:python:*:*
– langflow-ai langflow < 1.5.1
– langflow-ai langflow-base < 0.5.1
Original advisory text
Langflow: Authenticated Users Can Read, Modify, and Delete Any Flow via Missing Ownership Check
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to version 1.5.1, the `_read_flow` helper in `src/backend/base/langflow/api/v1/flows.py` branched on the `AUTO_LOGIN` setting to decide whether to filter by `user_id`. When `AUTO_LOGIN` was `False` (i.e., authentication was enabled), neither branch enforced an ownership check — the query returned any flow matching the given UUID regardless of who owned it. This allowed any authenticated user to read any other user's flow, including embedded plaintext API keys; modify the logic of another user's AI agents, and/or delete flows belonging to other users. The vulnerability was introduced by the conditional logic that was meant to accommodate public/example flows (those with `user_id = NULL`) under auto-login mode, but inadvertently left the authenticated path without an ownership filter. The fix in version 1.5.1 removes the `AUTO_LOGIN` conditional entirely and unconditionally scopes the query to the requesting user.
References
Fix within
Internet-facing 14 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker full control
Severity
9.4 Critical
Exploitation
<1% chance of attack within 30 days
Type
CWE-639Authorization Bypass Through User-Controlled Key
CWE-862Missing Authorization
Timeline
Published27 Mar 2026
Updated4 Nov 2026
First seen27 Mar 2026
Sources
GHSA-8c4j-f57c-35cf · GHSA
CVE-2026-34046 · NVD
GHSA-8c4j-f57c-35cf · OSV
CVE-2026-34046 · OSV
CVE-2026-34046 · MITRE
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