{"id":"CVE-2026-55255","aliases":["EUVD-2026-38517","GHSA-qrpv-q767-xqq2","PYSEC-2026-221","ROOT-APP-PYPI-CVE-2026-55255"],"status":"published","title":"Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow","description":"Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.","severity":{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00887,"percentile":0.59543,"model":"v2026.06.15"},"facts":{"in_kev":true,"known_exploited":true,"public_exploit":true,"fix_available":true},"cwes":["CWE-639"],"published":"2026-06-19T21:16:46Z","modified":"2026-10-28T02:30:24Z","kev":{"date_added":"2026-07-07","due_date":"2026-07-10","required_action":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","known_ransomware_use":"Unknown"},"exploitation":[{"source":"euvd","since":"2026-07-07"},{"source":"kev","since":"2026-07-07"}],"exploits":[{"source":"pocgithub","id":"rootdirective-sec/CVE-2026-55255-Lab","title":"rootdirective-sec/CVE-2026-55255-Lab","date":"2026-06-30","url":"https://github.com/rootdirective-sec/CVE-2026-55255-Lab"}],"fixes":[{"ecosystem":"PyPI","package":"langflow","fixed_in":["1.9.1","1.9.2"],"sources":["ghsa","osv"]},{"ecosystem":"Root:PyPI","package":"langflow","fixed_in":["1.9.0+aikido.2","1.8.4+aikido.2","1.8.1+aikido.2","1.7.3+aikido.2","1.7.0+aikido.2","1.6.9+aikido.3","1.6.0+aikido.2","1.9.0+aikido.3"],"sources":["osv"]},{"ecosystem":"Root:PyPI","package":"rootio-langflow","fixed_in":["1.9.0+root.io.2","1.8.4+root.io.2","1.8.1+root.io.2","1.7.3+root.io.2","1.7.0+root.io.2","1.6.9+root.io.3","1.6.0+root.io.2"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"langflow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.1"}]}]},{"source":"osv","ecosystem":"PyPI","package":"langflow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.1"}]}],"versions":["0.0.31","0.0.32","0.0.33","0.0.40","0.0.44","0.0.45","0.0.46","0.0.52","0.0.53","0.0.54","0.0.55","0.0.56","0.0.57","0.0.58","0.0.61","0.0.62","0.0.63","0.0.64","0.0.65","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","0.0.78","0.0.79","0.0.80","0.0.81","0.0.83","0.0.84","0.0.85","0.0.86","0.0.87","0.0.88","0.0.89","0.1.0","0.1.2","0.1.3","0.1.4","0.1.5","0.1.6","0.1.7","0.2.0","0.2.1","0.2.10","0.2.11","0.2.12","0.2.13","0.2.2","0.2.3","0.2.4","0.2.5","0.2.6","0.2.7","0.2.8","0.2.9","0.3.0","0.3.1","0.3.2","0.3.3","0.3.4","0.4.0","0.4.1","0.4.10","0.4.11","0.4.12","0.4.14","0.4.15","0.4.16","0.4.17","0.4.18","0.4.19","0.4.2","0.4.20","0.4.21","0.4.3","0.4.4","0.4.5","0.4.6","0.4.7","0.4.8","0.4.9","0.5.0","0.5.0a0","0.5.0a1","0.5.0a2","0.5.0a3","0.5.0a4","0.5.0a5","0.5.0a6","0.5.0b0","0.5.0b2","0.5.0b3","0.5.0b4","0.5.0b5","0.5.0b6","0.5.1","0.5.10","0.5.11","0.5.12","0.5.2","0.5.3","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.5.9","0.6.0","0.6.0rc1","0.6.1","0.6.10","0.6.11","0.6.12","0.6.14","0.6.15","0.6.16","0.6.17","0.6.18","0.6.19","0.6.2","0.6.3","0.6.3a0","0.6.3a1","0.6.3a2","0.6.3a3","0.6.3a4","0.6.3a5","0.6.3a6","0.6.3a7","0.6.4","0.6.4a0","0.6.4a1","0.6.5","0.6.5a0","0.6.5a1","0.6.5a10","0.6.5a11","0.6.5a12","0.6.5a13","0.6.5a2","0.6.5a3","0.6.5a4","0.6.5a5","0.6.5a6","0.6.5a7","0.6.5a8","0.6.5a9","0.6.6","0.6.7","0.6.7a1","0.6.7a2","0.6.7a3","0.6.7a5","0.6.8","0.6.9","1.0.0","1.0.0a0","1.0.0a1","1.0.0a10","1.0.0a11","1.0.0a12","1.0.0a13","1.0.0a14","1.0.0a15","1.0.0a17","1.0.0a18","1.0.0a19","1.0.0a2","1.0.0a20","1.0.0a21","1.0.0a22","1.0.0a23","1.0.0a24","1.0.0a25","1.0.0a26","1.0.0a27","1.0.0a28","1.0.0a29","1.0.0a3","1.0.0a30","1.0.0a31","1.0.0a32","1.0.0a33","1.0.0a34","1.0.0a35","1.0.0a36","1.0.0a37","1.0.0a38","1.0.0a39","1.0.0a4","1.0.0a40","1.0.0a41","1.0.0a42","1.0.0a43","1.0.0a44","1.0.0a45","1.0.0a46","1.0.0a47","1.0.0a48","1.0.0a49","1.0.0a5","1.0.0a50","1.0.0a51","1.0.0a52","1.0.0a53","1.0.0a55","1.0.0a56","1.0.0a57","1.0.0a58","1.0.0a59","1.0.0a6","1.0.0a60","1.0.0a61","1.0.0a7","1.0.0a8","1.0.0a9","1.0.0rc0","1.0.0rc1","1.0.1","1.0.10","1.0.11","1.0.12","1.0.13","1.0.14","1.0.15","1.0.16","1.0.17","1.0.18","1.0.19","1.0.19.post1","1.0.19.post2","1.0.2","1.0.3","1.0.4","1.0.5","1.0.6","1.0.7","1.0.8","1.0.9","1.1.0","1.1.1","1.1.2","1.1.3","1.1.4","1.1.4.post1","1.2.0","1.3.0","1.3.1","1.3.2","1.3.3","1.3.4","1.4.0","1.4.1","1.4.2","1.4.3","1.5.0","1.5.0.post1","1.5.0.post2","1.5.1","1.6.0","1.6.1","1.6.2","1.6.3","1.6.4","1.6.5","1.6.6","1.6.7","1.6.8","1.6.9","1.7.0","1.7.1","1.7.2","1.7.3","1.8.0","1.8.0rc0","1.8.0rc1","1.8.0rc2","1.8.0rc3","1.8.0rc4","1.8.0rc5","1.8.0rc6","1.8.1","1.8.2","1.8.3","1.8.3rc0","1.8.4","1.9.0"]},{"source":"osv","ecosystem":"PyPI","package":"langflow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.2"}]}],"versions":["0.0.31","0.0.32","0.0.33","0.0.40","0.0.44","0.0.45","0.0.46","0.0.52","0.0.53","0.0.54","0.0.55","0.0.56","0.0.57","0.0.58","0.0.61","0.0.62","0.0.63","0.0.64","0.0.65","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","0.0.78","0.0.79","0.0.80","0.0.81","0.0.83","0.0.84","0.0.85","0.0.86","0.0.87","0.0.88","0.0.89","0.1.0","0.1.2","0.1.3","0.1.4","0.1.5","0.1.6","0.1.7","0.2.0","0.2.1","0.2.10","0.2.11","0.2.12","0.2.13","0.2.2","0.2.3","0.2.4","0.2.5","0.2.6","0.2.7","0.2.8","0.2.9","0.3.0","0.3.1","0.3.2","0.3.3","0.3.4","0.4.0","0.4.1","0.4.10","0.4.11","0.4.12","0.4.14","0.4.15","0.4.16","0.4.17","0.4.18","0.4.19","0.4.2","0.4.20","0.4.21","0.4.3","0.4.4","0.4.5","0.4.6","0.4.7","0.4.8","0.4.9","0.5.0","0.5.0a0","0.5.0a1","0.5.0a2","0.5.0a3","0.5.0a4","0.5.0a5","0.5.0a6","0.5.0b0","0.5.0b2","0.5.0b3","0.5.0b4","0.5.0b5","0.5.0b6","0.5.1","0.5.10","0.5.11","0.5.12","0.5.2","0.5.3","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.5.9","0.6.0","0.6.0rc1","0.6.1","0.6.10","0.6.11","0.6.12","0.6.14","0.6.15","0.6.16","0.6.17","0.6.18","0.6.19","0.6.2","0.6.3","0.6.3a0","0.6.3a1","0.6.3a2","0.6.3a3","0.6.3a4","0.6.3a5","0.6.3a6","0.6.3a7","0.6.4","0.6.4a0","0.6.4a1","0.6.5","0.6.5a0","0.6.5a1","0.6.5a10","0.6.5a11","0.6.5a12","0.6.5a13","0.6.5a2","0.6.5a3","0.6.5a4","0.6.5a5","0.6.5a6","0.6.5a7","0.6.5a8","0.6.5a9","0.6.6","0.6.7","0.6.7a1","0.6.7a2","0.6.7a3","0.6.7a5","0.6.8","0.6.9","1.0.0","1.0.0a0","1.0.0a1","1.0.0a10","1.0.0a11","1.0.0a12","1.0.0a13","1.0.0a14","1.0.0a15","1.0.0a17","1.0.0a18","1.0.0a19","1.0.0a2","1.0.0a20","1.0.0a21","1.0.0a22","1.0.0a23","1.0.0a24","1.0.0a25","1.0.0a26","1.0.0a27","1.0.0a28","1.0.0a29","1.0.0a3","1.0.0a30","1.0.0a31","1.0.0a32","1.0.0a33","1.0.0a34","1.0.0a35","1.0.0a36","1.0.0a37","1.0.0a38","1.0.0a39","1.0.0a4","1.0.0a40","1.0.0a41","1.0.0a42","1.0.0a43","1.0.0a44","1.0.0a45","1.0.0a46","1.0.0a47","1.0.0a48","1.0.0a49","1.0.0a5","1.0.0a50","1.0.0a51","1.0.0a52","1.0.0a53","1.0.0a55","1.0.0a56","1.0.0a57","1.0.0a58","1.0.0a59","1.0.0a6","1.0.0a60","1.0.0a61","1.0.0a7","1.0.0a8","1.0.0a9","1.0.0rc0","1.0.0rc1","1.0.1","1.0.10","1.0.11","1.0.12","1.0.13","1.0.14","1.0.15","1.0.16","1.0.17","1.0.18","1.0.19","1.0.19.post1","1.0.19.post2","1.0.2","1.0.3","1.0.4","1.0.5","1.0.6","1.0.7","1.0.8","1.0.9","1.1.0","1.1.1","1.1.2","1.1.3","1.1.4","1.1.4.post1","1.2.0","1.3.0","1.3.1","1.3.2","1.3.3","1.3.4","1.4.0","1.4.1","1.4.2","1.4.3","1.5.0","1.5.0.post1","1.5.0.post2","1.5.1","1.6.0","1.6.1","1.6.2","1.6.3","1.6.4","1.6.5","1.6.6","1.6.7","1.6.8","1.6.9","1.7.0","1.7.1","1.7.2","1.7.3","1.8.0","1.8.0rc0","1.8.0rc1","1.8.0rc2","1.8.0rc3","1.8.0rc4","1.8.0rc5","1.8.0rc6","1.8.1","1.8.2","1.8.3","1.8.3rc0","1.8.4","1.9.0","1.9.1"]},{"source":"osv","ecosystem":"Root:PyPI","package":"langflow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.0+aikido.2"},{"fixed":"1.8.4+aikido.2"},{"fixed":"1.8.1+aikido.2"},{"fixed":"1.7.3+aikido.2"},{"fixed":"1.7.0+aikido.2"},{"fixed":"1.6.9+aikido.3"},{"fixed":"1.6.0+aikido.2"},{"fixed":"1.9.0+aikido.3"}]}]},{"source":"osv","ecosystem":"Root:PyPI","package":"rootio-langflow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.0+root.io.2"},{"fixed":"1.8.4+root.io.2"},{"fixed":"1.8.1+root.io.2"},{"fixed":"1.7.3+root.io.2"},{"fixed":"1.7.0+root.io.2"},{"fixed":"1.6.9+root.io.3"},{"fixed":"1.6.0+root.io.2"}]}]}],"products":[{"vendor":"langflow","product":"langflow"},{"vendor":"langflow-ai","product":"langflow"}],"references":[{"url":"https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2","tags":["x_refsource_CONFIRM","exploit","Exploit","Mitigation","Vendor Advisory","advisory","web","evidence"]},{"url":"https://github.com/langflow-ai/langflow/pull/12832","tags":["x_refsource_MISC","Issue Tracking","Patch","fix","web"]},{"url":"https://github.com/langflow-ai/langflow/commit/2c9f498d664a3c32698b57d7c5e752625291060e","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://webflow.sysdig.com/blog/understanding-langflow-cve-2026-55255-and-why-higher-cvss-vulnerabilities-arent-always-the-most-exploited","tags":["third-party-advisory","Third Party Advisory","advisory","web"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55255","tags":["government-resource","US Government Resource","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55255","tags":["advisory"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/langflow/PYSEC-2026-221.yaml","tags":["web"]},{"url":"https://github.com/advisories/GHSA-qrpv-q767-xqq2"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55255.json","tags":["advisory"]},{"url":"https://github.com/langflow-ai/langflow","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-55255","title":"Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow","description":"Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.","status":"published","published":"2026-06-23T16:28:20.985Z","modified":"2026-10-07T18:13:46.054Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","level":"high","assessor":"cna"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T14:20:11.925815Z"}],"euvd":[{"id":"EUVD-2026-38517","description":"Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.","status":"published","published":"2026-06-23T16:28:20Z","modified":"2026-10-07T18:13:46Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","level":"high"}],"exploited_since":"2026-07-07","updated_at":"2026-11-02T17:27:34.353796Z"}],"ghsa":[{"id":"GHSA-qrpv-q767-xqq2","title":"Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow","description":"## Summary\n\nInsecure Direct Object Reference (IDOR) vulnerability in `/api/v1/responses` endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request.\n\n## Details\n\nThe vulnerability exists in the `get_flow_by_id_or_endpoint_name` helper function in [`src/backend/base/langflow/helpers/flow.py` (lines 399-414)](https://github.com/langflow-ai/langflow/blob/v1.9.0/src/backend/base/langflow/helpers/flow.py#L399C1-L414C67).\n\nWhen a flow is accessed via UUID (flow_id), the function queries the database directly without verifying if the authenticated user owns that flow:\n\n```python\n# src/backend/base/langflow/helpers/flow.py:399-414\nasync def get_flow_by_id_or_endpoint_name(flow_id_or_name: str, user_id: str | UUID | None = None) -\u003e FlowRead:\n    async with session_scope() as session:\n        try:\n            flow_id = UUID(flow_id_or_name)\n            # When using UUID, query directly WITHOUT checking user_id\n            flow = await session.get(Flow, flow_id)  # ❌ No user_id check!\n        except ValueError:\n            endpoint_name = flow_id_or_name\n            stmt = select(Flow).where(Flow.endpoint_name == endpoint_name)\n            # Only when using endpoint_name is user_id checked\n            if user_id:\n                stmt = stmt.where(Flow.user_id == uuid_user_id)\n```\n\nThis function is used by the `/api/v1/responses` endpoint (defined in [`src/backend/base/langflow/api/v1/openai_responses.py:589`](https://github.com/langflow-ai/langflow/blob/v1.9.0/src/backend/base/langflow/api/v1/openai_responses.py#L589)).\n\n## PoC (Proof of Concept)\n\n```bash\n# Attacker (user A) with API_KEY_A tries to execute victim (user B)'s flow\ncurl -X POST \"http://localhost:7860/api/v1/responses\" \\\n  -H \"x-api-key: sk-ATTACKER_API_KEY\" \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\n    \"model\": \"VICTIM_FLOW_ID\",\n    \"input_value\": \"test\",\n    \"stream\": false\n  }'\n# Returns 200 and executes the victim's flow\n```\n\n## Impact\n\nAny authenticated user can:\n1. Execute any flow in the system by knowing its flow ID\n2. Access potentially sensitive data processed by victim's flows\n3. Consume victim's resources\n\n## Fixes\n\nFixed in **PR #12832** (`fix(security): close IDOR in get_flow_by_id_or_endpoint_name`), merged 2026-04-22, released in **Langflow 1.9.1**.\n\nThe helper normalizes `user_id` once and enforces ownership on **both** lookup branches (UUID *and* `endpoint_name`):\n\n```python\nflow_id = UUID(flow_id_or_name)\nflow = await session.get(Flow, flow_id)\nif flow is not None and uuid_user_id is not None and flow.user_id != uuid_user_id:\n    flow = None  # cross-user lookup falls through to the shared 404\n```\n\nKey points:\n- Cross-user lookups return **404** (not 403), so flow existence is not disclosed via a 403-vs-404 oracle.\n- `/api/v1/responses` and `/api/v2/workflow` pass `user_id` explicitly, so fixing the helper closes them directly; the `/api/v1/run*` routes were additionally moved from a bare `Depends(get_flow_by_id_or_endpoint_name)` to auth-aware wrapper dependencies (defense in depth).\n- A malformed `user_id` now fails closed (404 instead of a raw 500).\n- Webhook routes intentionally keep the unscoped lookup (public by design / explicit ownership check elsewhere).\n- Regression tests cover the cross-user UUID case and reproduce the original PoC against `/api/v1/responses`.\n\n\n\n\n\n## Acknowledgements\n\nThanks to the security researchers who responsibly disclosed this vulnerability:\n* @yzeirnials\n* @johnatzeropath\n* @LeftenantZero\n* @Zwique","status":"published","published":"2026-06-19T21:16:46Z","modified":"2026-07-07T22:14:37Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","level":"high"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T14:40:40.389795Z"}],"kev":[{"id":"CVE-2026-55255","title":"Langflow Authorization Bypass Through User-Controlled Key Vulnerability","description":"Langflow contains an authorization bypass through user-controlled key vulnerability which allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request.","cwes":["CWE-639"],"kev":{"date_added":"2026-07-07","due_date":"2026-07-10","required_action":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","known_ransomware_use":"Unknown"},"updated_at":"2026-11-02T17:00:15.999436Z"}],"nvd":[{"id":"CVE-2026-55255","description":"Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.","status":"published","published":"2026-06-23T17:17:08.05Z","modified":"2026-10-25T23:10:00.167Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","level":"high","assessor":"secondary"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T14:12:25.288279Z"}],"osv":[{"id":"CVE-2026-55255","title":"Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow","description":"Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.","status":"published","published":"2026-06-23T16:28:20.985Z","modified":"2026-10-28T02:30:24.276714914Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","level":"high"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T15:45:11.22012Z"},{"id":"GHSA-qrpv-q767-xqq2","title":"Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow","description":"## Summary\n\nInsecure Direct Object Reference (IDOR) vulnerability in `/api/v1/responses` endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request.\n\n## Details\n\nThe vulnerability exists in the `get_flow_by_id_or_endpoint_name` helper function in [`src/backend/base/langflow/helpers/flow.py` (lines 399-414)](https://github.com/langflow-ai/langflow/blob/v1.9.0/src/backend/base/langflow/helpers/flow.py#L399C1-L414C67).\n\nWhen a flow is accessed via UUID (flow_id), the function queries the database directly without verifying if the authenticated user owns that flow:\n\n```python\n# src/backend/base/langflow/helpers/flow.py:399-414\nasync def get_flow_by_id_or_endpoint_name(flow_id_or_name: str, user_id: str | UUID | None = None) -\u003e FlowRead:\n    async with session_scope() as session:\n        try:\n            flow_id = UUID(flow_id_or_name)\n            # When using UUID, query directly WITHOUT checking user_id\n            flow = await session.get(Flow, flow_id)  # ❌ No user_id check!\n        except ValueError:\n            endpoint_name = flow_id_or_name\n            stmt = select(Flow).where(Flow.endpoint_name == endpoint_name)\n            # Only when using endpoint_name is user_id checked\n            if user_id:\n                stmt = stmt.where(Flow.user_id == uuid_user_id)\n```\n\nThis function is used by the `/api/v1/responses` endpoint (defined in [`src/backend/base/langflow/api/v1/openai_responses.py:589`](https://github.com/langflow-ai/langflow/blob/v1.9.0/src/backend/base/langflow/api/v1/openai_responses.py#L589)).\n\n## PoC (Proof of Concept)\n\n```bash\n# Attacker (user A) with API_KEY_A tries to execute victim (user B)'s flow\ncurl -X POST \"http://localhost:7860/api/v1/responses\" \\\n  -H \"x-api-key: sk-ATTACKER_API_KEY\" \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\n    \"model\": \"VICTIM_FLOW_ID\",\n    \"input_value\": \"test\",\n    \"stream\": false\n  }'\n# Returns 200 and executes the victim's flow\n```\n\n## Impact\n\nAny authenticated user can:\n1. Execute any flow in the system by knowing its flow ID\n2. Access potentially sensitive data processed by victim's flows\n3. Consume victim's resources\n\n## Fixes\n\nFixed in **PR #12832** (`fix(security): close IDOR in get_flow_by_id_or_endpoint_name`), merged 2026-04-22, released in **Langflow 1.9.1**.\n\nThe helper normalizes `user_id` once and enforces ownership on **both** lookup branches (UUID *and* `endpoint_name`):\n\n```python\nflow_id = UUID(flow_id_or_name)\nflow = await session.get(Flow, flow_id)\nif flow is not None and uuid_user_id is not None and flow.user_id != uuid_user_id:\n    flow = None  # cross-user lookup falls through to the shared 404\n```\n\nKey points:\n- Cross-user lookups return **404** (not 403), so flow existence is not disclosed via a 403-vs-404 oracle.\n- `/api/v1/responses` and `/api/v2/workflow` pass `user_id` explicitly, so fixing the helper closes them directly; the `/api/v1/run*` routes were additionally moved from a bare `Depends(get_flow_by_id_or_endpoint_name)` to auth-aware wrapper dependencies (defense in depth).\n- A malformed `user_id` now fails closed (404 instead of a raw 500).\n- Webhook routes intentionally keep the unscoped lookup (public by design / explicit ownership check elsewhere).\n- Regression tests cover the cross-user UUID case and reproduce the original PoC against `/api/v1/responses`.\n\n\n\n\n\n## Acknowledgements\n\nThanks to the security researchers who responsibly disclosed this vulnerability:\n* @yzeirnials\n* @johnatzeropath\n* @LeftenantZero\n* @Zwique","status":"published","published":"2026-06-19T21:16:46Z","modified":"2026-07-07T22:30:08.905598564Z","cvss":[{"version":"3.1","score":8.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L","level":"high"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T15:46:54.760124Z"},{"id":"PYSEC-2026-221","description":"Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.2, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.2.","status":"published","published":"2026-06-23T17:17:08.05Z","modified":"2026-06-26T00:00:06.061343789Z","cvss":[{"version":"3.1","score":9.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L","level":"critical"}],"updated_at":"2026-11-02T15:52:55.537808Z"},{"id":"ROOT-APP-PYPI-CVE-2026-55255","title":"CVE-2026-55255 in langflow - Patched by Root","description":"Root has patched CVE-2026-55255 in the langflow package for Root:PyPI. Multiple fixed versions available.","status":"published","published":"2026-08-05T10:23:46Z","modified":"2026-08-05T12:30:16.624913641Z","updated_at":"2026-11-02T15:53:28.259095Z"}]}}