Langflow Missing Authentication on Critical API Endpoints

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.8 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2026-21445: 33.29% estimated exploitation activity in the next 30 days; percentile 98.37 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Multiple critical API endpoints in Langflow are missing authentication controls, allowing any unauthenticated user to access sensitive user conversation data, transaction histories, and perform destructive operations including message deletion. This affects endpoints handling personal data and system operations that should require proper authorization. Details The vulnerability exists in three API endpoints within src/backend/base/langflow/api/v1/monitor.py that are missing the required dependencies=[Depends(getcurrentactiveuser)] authentication dependency: Affected Endpoints: 1. GET /api/v1/monitor/messages (Line 61) 2. GET /api/v1/monitor/transactions (Line 183) 3. DELETE /api/v1/monitor/messages/session/{sessionid} (Line 165) Inconsistency Evidence: Other endpoints in the same file properly implement authentication: PoC Complete reproduction steps to demonstrate the vulnerability: Prerequisites: 1. Start a Langflow server instance 2. Ensure no authentication headers or API…

Published by the source

2 Jan 2026, 21:11 UTC

Last modified by the source

13 Jul 2026, 16:43 UTC

Source last checked

26 Oct 2026, 13:36 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-c5cp-vx83-jhqx

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-c5cp-vx83-jhqx

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# Patch Next advisory brief: CVE-2026-21445

Advisory: Langflow Missing Authentication on Critical API Endpoints
IDs: CVE-2026-21445, GHSA-c5cp-vx83-jhqx
Record: https://patchnext.com/advisories/cve-2026-21445 (revision 3, source checked 26 Oct 2026, 13:36 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: langflow-base 0.7.1; langflow 1.7.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI langflow-base: affected <= 0.6.9; fixed in 0.7.1
- PyPI langflow: affected <= 1.7.0.dev44; fixed in 1.7.1

## Suggested inspection (read-only)
- `python -m pip show langflow-base`: prints the installed version. Run with the environment that serves production active.
- `python -m pip show langflow`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on langflow-base, langflow.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-c5cp-vx83-jhqx (OSV record GHSA-c5cp-vx83-jhqx lists affected ranges: PyPI langflow-base >=0 =0 <1.7.1 (fixed))
- Verified: https://github.com/advisories/GHSA-c5cp-vx83-jhqx (GitHub-reviewed advisory GHSA-c5cp-vx83-jhqx lists affected ranges: PyPI langflow-base >=0 =0 <=1.7.0.dev44)

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