PYSEC-2026-2570

Vulnerability from pysec - Published: 2026-07-13 14:36 - Updated: 2026-07-13 16:04
VLAI
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:

Impacted products
Name purl
langflow-base pkg:pypi/langflow-base

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "langflow-base",
        "purl": "pkg:pypi/langflow-base"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.5.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.0.13",
        "0.0.14",
        "0.0.15",
        "0.0.16",
        "0.0.17",
        "0.0.18",
        "0.0.19",
        "0.0.20",
        "0.0.21",
        "0.0.22",
        "0.0.23",
        "0.0.24",
        "0.0.25",
        "0.0.26",
        "0.0.27",
        "0.0.28",
        "0.0.29",
        "0.0.30",
        "0.0.31",
        "0.0.32",
        "0.0.33",
        "0.0.34",
        "0.0.35",
        "0.0.36",
        "0.0.37",
        "0.0.38",
        "0.0.39",
        "0.0.40",
        "0.0.41",
        "0.0.42",
        "0.0.43",
        "0.0.44",
        "0.0.45",
        "0.0.46",
        "0.0.47",
        "0.0.48",
        "0.0.49",
        "0.0.50",
        "0.0.51",
        "0.0.52",
        "0.0.53",
        "0.0.54",
        "0.0.55",
        "0.0.56",
        "0.0.57",
        "0.0.58",
        "0.0.59",
        "0.0.60",
        "0.0.61",
        "0.0.62",
        "0.0.63",
        "0.0.64",
        "0.0.66",
        "0.0.67",
        "0.0.68",
        "0.0.69",
        "0.0.70",
        "0.0.71",
        "0.0.72",
        "0.0.73",
        "0.0.74",
        "0.0.75",
        "0.0.76",
        "0.0.77",
        "0.0.78",
        "0.0.79",
        "0.0.80",
        "0.0.81",
        "0.0.82",
        "0.0.83",
        "0.0.84",
        "0.0.85",
        "0.0.86",
        "0.0.87",
        "0.0.88",
        "0.0.89",
        "0.0.90",
        "0.0.91",
        "0.0.92",
        "0.0.93",
        "0.0.94",
        "0.0.95",
        "0.0.96",
        "0.0.97",
        "0.0.98",
        "0.0.99",
        "0.1.0",
        "0.1.1",
        "0.1.2",
        "0.1.3",
        "0.1.4",
        "0.1.4.post1",
        "0.2.0",
        "0.3.0",
        "0.3.1",
        "0.3.2",
        "0.3.3",
        "0.3.4",
        "0.4.0",
        "0.4.1",
        "0.4.2",
        "0.4.3",
        "0.5.0",
        "0.5.0.post1",
        "0.5.0.post2"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34046",
    "GHSA-8c4j-f57c-35cf"
  ],
  "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": "PYSEC-2026-2570",
  "modified": "2026-07-13T16:04:31.460104Z",
  "published": "2026-07-13T14:36:45.537461Z",
  "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"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/langflow-base"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-8c4j-f57c-35cf"
    }
  ],
  "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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