Advisory details:
pypa / langflow/PYSEC-2026-2567
| Advisory ID | pypa/langflow/PYSEC-2026-2567 |
| Aliases |
CVE-2026-34046
GHSA-8c4j-f57c-35cf PYSEC-2026-2567 |
| Summary | Langflow: Authenticated Users Can Read, Modify, and Delete Any Flow via Missing Ownership Check ## Vulnerability ### IDOR in `GET/PATCH/DELETE /api/v1/flow/{flow_id}` 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 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 `user_id = NULL`) under auto-login mode, but inadvertently left the authenticated path without an ownership filter. --- ## Fix (PR #8956) The fix removes the `AUTO_LOGIN` conditional entirely and unconditionally scopes the query to the requesting user: ```diff - auth_settings = settings_service.auth_settings - stmt = select(Flow).where(Flow.id == flow_id) - if auth_settings.AUTO_LOGIN: - stmt = stmt.where( - (Flow.user_id == user_id) | (Flow.user_id == None) # noqa: E711 - ) + stmt = select(Flow).where(Flow.id == flow_id).where(Flow.user_id == user_id) ``` All three operations — read, update, and delete — route through `_read_flow`, so the single change covers the full attack surface. A cross-user isolation test (`test_read_flows_user_isolation`) was added to prevent regression. --- ## Acknowledgements Langflow thanks the security researcher who responsibly disclosed this vulnerability: - **[@chximn-dt](https://github.com/chximn-dt)** |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 7.8 |
| Risk | 3.9 |
| Affected and Fixed Packages | Package Details |
| Introduced and Fixed Package Commit Patches | Package Commit Patches Details |
| There are no known CWE. |
| System | Score | Found at |
|---|---|---|
| cvssv4 | 8.7 | https://github.com/pypa/advisory-database/blob/main/vulns/langflow/PYSEC-2026-2567.yaml |
| Reference id | Reference type | URL |
|---|---|---|
| https://github.com/langflow-ai/langflow | ||
| https://pypi.org/project/langflow | ||
| 8956 | Other | https://github.com/langflow-ai/langflow/pull/8956 |
| CVE-2026-34046 | https://nvd.nist.gov/vuln/detail/CVE-2026-34046 | |
| GHSA-8c4j-f57c-35cf | https://github.com/advisories/GHSA-8c4j-f57c-35cf | |
| GHSA-8c4j-f57c-35cf | Other | https://github.com/langflow-ai/langflow/security/advisories/GHSA-8c4j-f57c-35cf |
No EPSS data available for this advisory.
| Patch URL | |
|---|---|
| There are no known patches. | |
| Attack Vector (AV) | Attack Complexity (AC) | Attack Requirements (AT) | Privileges Required (PR) | User Interaction (UI) | Vulnerable System Impact Confidentiality (VC) | Vulnerable System Impact Integrity (VI) | Vulnerable System Impact Availability (VA) | Subsequent System Impact Confidentiality (SC) | Subsequent System Impact Integrity (SI) | Subsequent System Impact Availability (SA) |
|---|---|---|---|---|---|---|---|---|---|---|
network adjacent local physical |
low high |
none present |
none low high |
none passive active |
high low none |
high low none |
high low none |
high low none |
high low none |
high low none |
Vector: SSVCv2/E:N/A:N/T:P/P:M/B:A/M:M/D:T/2026-03-31T13:57:05Z/
Decision: Track
Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/34xxx/CVE-2026-34046.json
Source Advisory: vulnrichment/CVE-2026-34046
[{'Exploitation': 'none'},
{'Automatable': 'no'},
{'Technical Impact': 'partial'},
{'Mission Prevalence': 'minimal'},
{'Public Well-being Impact': 'material'},
{'Mission & Well-being': 'medium'}]