Langflow: Authenticated Users Can Read, Modify, and Delete Any Flow via Missing Ownership Check

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-34046: 0.48% estimated exploitation activity in the next 30 days; percentile 41.23 (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.

Vulnerability IDOR in GET/PATCH/DELETE /api/v1/flow/{flowid} The readflow helper in src/backend/base/langflow/api/v1/flows.py branched on the AUTOLOGIN setting to decide whether to filter by userid. When AUTOLOGIN 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 exposed any authenticated user to: - Read any other user's flow, including embedded plaintext API keys - Modify the logic of another user's AI agents - Delete flows belonging to other users The vulnerability was introduced by the conditional logic that was meant to accommodate public/example flows (those with userid = NULL) under auto-login mode, but inadvertently left the authenticated path without an ownership filter. --- Fix (PR #8956) The fix removes the AUTOLOGIN conditional entirely and unconditionally scopes the query to the requesting user: All three operations — read, update, and delete —…

Published by the source

27 Mar 2026, 19:36 UTC

Last modified by the source

13 Jul 2026, 16:43 UTC

Source last checked

26 Oct 2026, 13:40 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-8c4j-f57c-35cf

2. Revision 2 · amended · 25 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-8c4j-f57c-35cf

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# Patch Next advisory brief: CVE-2026-34046

Advisory: Langflow: Authenticated Users Can Read, Modify, and Delete Any Flow via Missing Ownership Check
IDs: CVE-2026-34046, GHSA-8c4j-f57c-35cf
Record: https://patchnext.com/advisories/cve-2026-34046 (revision 3, source checked 26 Oct 2026, 13:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: langflow-base 0.5.1; langflow 1.5.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI langflow-base: affected <= 0.5.0; fixed in 0.5.1
- PyPI langflow: affected <= 1.5.0; fixed in 1.5.1

## 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-8c4j-f57c-35cf (OSV record GHSA-8c4j-f57c-35cf lists affected ranges: PyPI langflow >=0 =0 <0.5.1 (fixed))
- Verified: https://github.com/advisories/GHSA-8c4j-f57c-35cf (GitHub-reviewed advisory GHSA-8c4j-f57c-35cf lists affected ranges: PyPI langflow >=0 =0 <=0.5.0)

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