GHSA-8C4J-F57C-35CF
Vulnerability from github – Published: 2026-03-27 19:36 – Updated: 2026-03-27 21:52
VLAI?
Summary
Langflow: Authenticated Users Can Read, Modify, and Delete Any Flow via Missing Ownership Check
Details
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:
- 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:
Severity ?
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.5.0"
},
"package": {
"ecosystem": "PyPI",
"name": "langflow"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.5.1"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.5.0"
},
"package": {
"ecosystem": "PyPI",
"name": "langflow-base"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.5.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-34046"
],
"database_specific": {
"cwe_ids": [
"CWE-639",
"CWE-862"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-27T19:36:23Z",
"nvd_published_at": "2026-03-27T21:17:27Z",
"severity": "HIGH"
},
"details": "## Vulnerability\n\n### IDOR in `GET/PATCH/DELETE /api/v1/flow/{flow_id}`\n\nThe `_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 \u2014 the query returned any flow matching the given UUID regardless of who owned it.\n\nThis exposed any authenticated user to:\n\n- **Read** any other user\u0027s flow, including embedded plaintext API keys\n- **Modify** the logic of another user\u0027s AI agents\n- **Delete** flows belonging to other users\n\nThe 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.\n\n---\n\n## Fix (PR #8956)\n\nThe fix removes the `AUTO_LOGIN` conditional entirely and unconditionally scopes the query to the requesting user:\n\n```diff\n- auth_settings = settings_service.auth_settings\n- stmt = select(Flow).where(Flow.id == flow_id)\n- if auth_settings.AUTO_LOGIN:\n- stmt = stmt.where(\n- (Flow.user_id == user_id) | (Flow.user_id == None) # noqa: E711\n- )\n+ stmt = select(Flow).where(Flow.id == flow_id).where(Flow.user_id == user_id)\n```\n\nAll three operations \u2014 read, update, and delete \u2014 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.\n\n---\n\n## Acknowledgements\n\nLangflow thanks the security researcher who responsibly disclosed this vulnerability:\n\n- **[@chximn-dt](https://github.com/chximn-dt)**",
"id": "GHSA-8c4j-f57c-35cf",
"modified": "2026-03-27T21:52:39Z",
"published": "2026-03-27T19:36:23Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/langflow-ai/langflow/security/advisories/GHSA-8c4j-f57c-35cf"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34046"
},
{
"type": "WEB",
"url": "https://github.com/langflow-ai/langflow/pull/8956"
},
{
"type": "PACKAGE",
"url": "https://github.com/langflow-ai/langflow"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "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",
"type": "CVSS_V4"
}
],
"summary": "Langflow: Authenticated Users Can Read, Modify, and Delete Any Flow via Missing Ownership Check"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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