{
  "affected": [
    {
      "affectedData": [
        {
          "product": "diffusers",
          "vendor": "huggingface",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.38.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:huggingface:diffusers:*:*:*:*:*:python:*:*",
              "matchCriteriaId": "D7F2A2AE-D122-46BA-BD64-67DCF4C22677",
              "versionEndExcluding": "0.38.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Diffusers is the a library for  pretrained diffusion models. Prior to 0.38.0, diffusers 0.37.0 allows remote code execution without the trust_remote_code=True safeguard when loading pipelines from Hugging Face Hub repositories. The _resolve_custom_pipeline_and_cls function in pipeline_loading_utils.py performs string interpolation on the custom_pipeline parameter using f\"{custom_pipeline}.py\". When custom_pipeline is not supplied by the user, it defaults to None, which Python interpolates as the literal string \"None.py\". If an attacker publishes a Hub repository containing a file named None.py with a class that subclasses DiffusionPipeline, the file is automatically downloaded and executed during a standard DiffusionPipeline.from_pretrained() call with no additional keyword arguments. The trust_remote_code check in DiffusionPipeline.download() is bypassed because it evaluates custom_pipeline is not None as False (since the kwarg was never supplied), while the downstream code path that actually loads the module resolves the None value into a valid filename. An attacker can achieve silent arbitrary code execution by publishing a malicious model repository with a None.py file and a standard-looking model_index.json that references a legitimate pipeline class name, requiring only that a victim calls from_pretrained on the repository. This vulnerability is fixed in 0.38.0."
    }
  ],
  "id": "CVE-2026-44827",
  "lastModified": "2026-06-17T10:51:24.087",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-44827",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-05-14T18:00:53.494731Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-05-14T17:16:23.500",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/huggingface/diffusers/security/advisories/GHSA-j7w6-vpvq-j3gm"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/huggingface/diffusers/security/advisories/GHSA-j7w6-vpvq-j3gm"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-94"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "diffusers"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.38.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44827"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-07T02:24:22Z",
    "nvd_published_at": "2026-05-14T17:16:23Z",
    "severity": "HIGH"
  },
  "details": "## Background\n\nThis vulnerability is found in the `DiffusionPipeline.from_pretrained` flow, which is used to load a pipeline from the HuggingFace Hub.\n\nThis function accepts an optional `custom_pipeline` keyword argument: the name of a Python file in the repo that contains a custom class inheriting from `DiffusionPipeline`. An equivalent flow is triggered when the `_class_name` field in `model_index.json` (the repo config file) is set to a custom class.\n\nAny attempt to use a custom pipeline throws the following exception, requesting that `trust_remote_code` is also passed:\n\n```python\nDiffusionPipeline.from_pretrained(\n    pretrained_model_name_or_path=\u0027ido-shani/custom-pipeline\u0027,\n    custom_pipeline=\"custom\"\n)\n\nValueError: The repository for ido-shani/custom-pipeline contains custom code in\ncustom.py which must be executed to correctly load the model. You can inspect the\nrepository content at https://hf.co/ido-shani/custom-pipeline/blob/main/custom.py.\nPlease pass the argument `trust_remote_code=True` to allow custom code to be run.\n```\n\nThe vulnerability is a silent RCE - it allows arbitrary code to be loaded through the custom\\_pipeline flow from a Hub repo, with no `custom_pipeline` or `trust_remote_code` kwargs and nothing suspicious in the config. The `from_pretrained` call succeeds and returns a functional pipeline.\n\n## Naive Flow\n\nFirst, all relevant arguments are popped from kwargs and stored in local variables.\n\nGiven a `pretrained_model_name_or_path` that is a Hub repo ID, `DiffusionPipeline.download()` is called. This function serves two roles: it orchestrates downloading relevant model files, and it is the security gatekeeper for `trust_remote_code`. It is called even if the model is already cached; in that case it exits early. If the repo contains custom code, it checks whether `trust_remote_code` was passed and raises otherwise:\n\n```python\n# pipeline_utils.py:1645-1652\nload_pipe_from_hub = custom_pipeline is not None and f\"{custom_pipeline}.py\" in filenames\n\n...\n\nif load_pipe_from_hub and not trust_remote_code:\n    raise ValueError(...)\n```\n\nIt then runs `_get_pipeline_class`, which returns the class object of the pipeline in order to inspect its `__init__` signature and determine which component files need to be downloaded. As part of building the `allow_patterns` list used to filter the snapshot download to necessary files only, the custom pipeline file is explicitly included if present:\n\n```python\n# pipeline_utils.py:1707\nallow_patterns += [f\"{custom_pipeline}.py\"] if f\"{custom_pipeline}.py\" in filenames else []\n```\n\nThe function then checks if all expected files are already present, and either exits early or triggers a snapshot download with those patterns.\n\nThe next step in `from_pretrained` is loading the pipeline class a second time, this time to actually instantiate it. Before calling `_get_pipeline_class` again, `_resolve_custom_pipeline_and_cls` is called to translate the `custom_pipeline` name into a local path, since the files have already been downloaded:\n\n```python\n# pipeline_loading_utils.py:965-974\ndef _resolve_custom_pipeline_and_cls(folder, config, custom_pipeline):\n    custom_class_name = None\n    if os.path.isfile(os.path.join(folder, f\"{custom_pipeline}.py\")):\n        custom_pipeline = os.path.join(folder, f\"{custom_pipeline}.py\")\n    elif isinstance(config[\"_class_name\"], (list, tuple)) and os.path.isfile(\n        os.path.join(folder, f\"{config[\u0027_class_name\u0027][0]}.py\")\n    ):\n        custom_pipeline = os.path.join(folder, f\"{config[\u0027_class_name\u0027][0]}.py\")\n        custom_class_name = config[\"_class_name\"][1]\n\n    return custom_pipeline, custom_class_name\n```\n\nWhen `custom_class_name` is `None` (i.e. `custom_pipeline` was given as a kwarg rather than via the config), `_get_pipeline_class` will scan the file and automatically identify the class that subclasses `DiffusionPipeline`.\n\nOnce this is done, `_get_pipeline_class` is invoked with the resolved local path, which loads the custom code, retrieves the class object, and proceeds with instantiation.\n\n## The Vulnerability\n\n`_resolve_custom_pipeline_and_cls` receives `custom_pipeline` from the kwargs - when not supplied it defaults to `None`. That `None` is used in string formatting: `f\"{None}.py\"` = `\"None.py\"`.\n\n**If the repo contains a file with this name, it will be detected as a custom pipeline.**\n\nThis is only reached on the second invocation of `_get_pipeline_class` (inside `from_pretrained`, after `download()` returns). The trust\\_remote\\_code check lives entirely in `download()`, which evaluated `custom_pipeline is None -\u003e False` and skipped it. By the time `_resolve_custom_pipeline_and_cls` runs, it is no longer relevant.\n\nAs a bonus, `None.py` even gets downloaded automatically when the model isn\u0027t cached yet. This isn\u0027t strictly required - it is quite plausible that the victim has already run `hf download \u003cmodel\u003e` and has all files locally - but if they haven\u0027t, revisiting the `allow_patterns` line above shows it makes the same error: `f\"{None}.py\"` = `\"None.py\"` is added to `allow_patterns` and fetched.\n\nWhat should `None.py` contain? To avoid breaking the pipeline load, it must define a class inheriting from `DiffusionPipeline`. To avoid leaving suspicious clues in the config, that class should shadow one that already exists in diffusers. The following satisfies both requirements:\n\n```python\nfrom diffusers import FluxPipeline as _FluxPipeline\n\nclass FluxPipeline(_FluxPipeline):\n    pass\n\n# INSERT MALICIOUS CODE HERE\nimport pathlib\npathlib.Path(\"/tmp/pwned\").write_text(\":)\")\n```\n\nWith this, `model_index.json` can contain `\"_class_name\": \"FluxPipeline\"` - appearing to use the standard diffusers class - and the resulting pipeline is fully functional (it is also functional when running as a local directory). This has been verified against an extracted version of [DDUF/tiny-flux-dev-pipe-dduf](https://huggingface.co/DDUF/tiny-flux-dev-pipe-dduf).\n\nAll the attacker needs the victim to run is:\n\n```python\nfrom diffusers import DiffusionPipeline\n\npipeline = DiffusionPipeline.from_pretrained(\u0027ido-shani/none-py-trust-remote-code-bypass\u0027)\n```\n\n## PoC\n\n-   Upload this zip as a model to the hub. https://drive.google.com/file/d/1mULARMLJJUTCi57xIv0wtDauko-JW0h7/view?usp=sharing\n-   Run `DiffusionPipeline.from_pretrained` on the uploaded model hub identifier.\n-   RCE occured; `/tmp/pwned` was created. If you are running the exploit on windows, change the path touched in `None.py`.\n\n# Impact\n\nThe vulnerability is a silent RCE - it allows arbitrary code to be loaded through the custom\\_pipeline flow from a Hub repo, with no `custom_pipeline` or `trust_remote_code` kwargs and nothing suspicious in the config. The `from_pretrained` call succeeds and returns a functional pipeline.\n\n# Occurrences\n\nhttps://github.com/huggingface/diffusers/blob/e1b5db52bda85d47a4f8f75954f77e672a8f7f1c/src/diffusers/pipelines/pipeline_loading_utils.py#L976\n\n# Patches\n\nYes. Fixed in **diffusers 0.38.0** via [PR #13448](https://github.com/huggingface/diffusers/pull/13448). All users on versions `\u003c 0.38.0` should upgrade:\n\n```bash\npip install --upgrade \"diffusers\u003e=0.38.0\"\n```\n\nThe fix moves the `trust_remote_code` gate out of `DiffusionPipeline.download()` and into `get_cached_module_file` in `src/diffusers/utils/dynamic_modules_utils.py`, which is the actual chokepoint for every dynamic module load (local, Hub, or community mirror). All three variants now raise `ValueError` when trust_remote_code=False instead of executing untrusted code.  \n\n# Workarounds\n\nIf upgrading immediately is not possible:\n\n- Only call `from_pretrained` with `pretrained_model_name_or_path`, `custom_pipeline`, and local snapshot directories from sources you fully trust and have audited.\n- Do not pass `custom_pipeline=` pointing at a Hub repository different from the primary `pretrained_model_name_or_path` unless you have read its `pipeline.py`.\n- Before calling `from_pretrained` on a local snapshot, inspect the snapshot for unexpected `*.py` files, especially under component subdirectories (`unet/`, `scheduler/`, etc.) and at the snapshot root.\n\n# Why this should have a dedicated CVE\n\nGHSA-j7w6-vpvq-j3gm is a distinct defect from CVE-2026-44513. CVE-2026-44513 is a misplaced-security-gate bug requiring a user-supplied `custom_pipeline` argument or a config entry declaring custom code. GHSA-j7w6 is a string-formatting bug where the default custom_pipeline=None is interpolated into the filename `None.py`, allowing silent RCE on a fully default `from_pretrained(\u0027repo\u0027)` call with no kwargs and a `model_index.json` that shadows a legitimate class. The root cause root cause and trigger are different, although the fix applied to address CVE-2026-44513 also addresses this vulnerability.",
  "id": "GHSA-j7w6-vpvq-j3gm",
  "modified": "2026-06-05T17:53:00Z",
  "published": "2026-05-07T02:24:22Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/huggingface/diffusers/security/advisories/GHSA-j7w6-vpvq-j3gm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44827"
    },
    {
      "type": "WEB",
      "url": "https://github.com/huggingface/diffusers/pull/13448"
    },
    {
      "type": "WEB",
      "url": "https://github.com/huggingface/diffusers/commit/a37f6f8394ac2a7ee8360c3abea811efe54512b1"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/huggingface/diffusers"
    },
    {
      "type": "WEB",
      "url": "https://github.com/huggingface/diffusers/releases/tag/v0.38.0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/diffusers/PYSEC-2026-41.yaml"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Diffusers has a `trust_remote_code` bypass via `custom_pipeline` and local custom components",
  "withdrawn": "2026-05-07T05:25:32Z"
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "diffusers",
        "purl": "pkg:pypi/diffusers"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.38.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.0.1",
        "0.0.2",
        "0.0.3",
        "0.0.4",
        "0.1.0",
        "0.1.1",
        "0.1.2",
        "0.1.3",
        "0.10.0",
        "0.10.1",
        "0.10.2",
        "0.11.0",
        "0.11.1",
        "0.12.0",
        "0.12.1",
        "0.13.0",
        "0.13.1",
        "0.14.0",
        "0.15.0",
        "0.15.1",
        "0.16.0",
        "0.16.1",
        "0.17.0",
        "0.17.1",
        "0.18.0",
        "0.18.1",
        "0.18.2",
        "0.19.0",
        "0.19.1",
        "0.19.2",
        "0.19.3",
        "0.2.0",
        "0.2.1",
        "0.2.2",
        "0.2.3",
        "0.2.4",
        "0.20.0",
        "0.20.1",
        "0.20.2",
        "0.21.0",
        "0.21.1",
        "0.21.2",
        "0.21.3",
        "0.21.4",
        "0.22.0",
        "0.22.1",
        "0.22.2",
        "0.22.3",
        "0.23.0",
        "0.23.1",
        "0.24.0",
        "0.25.0",
        "0.25.1",
        "0.26.0",
        "0.26.1",
        "0.26.2",
        "0.26.3",
        "0.27.0",
        "0.27.1",
        "0.27.2",
        "0.28.0",
        "0.28.1",
        "0.28.2",
        "0.29.0",
        "0.29.1",
        "0.29.2",
        "0.3.0",
        "0.30.0",
        "0.30.1",
        "0.30.2",
        "0.30.3",
        "0.31.0",
        "0.32.0",
        "0.32.1",
        "0.32.2",
        "0.33.0",
        "0.33.1",
        "0.34.0",
        "0.35.0",
        "0.35.1",
        "0.35.2",
        "0.36.0",
        "0.37.0",
        "0.37.1",
        "0.4.0",
        "0.4.1",
        "0.4.2",
        "0.5.0",
        "0.5.1",
        "0.6.0",
        "0.7.0",
        "0.7.1",
        "0.7.2",
        "0.8.0",
        "0.8.1",
        "0.9.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44827",
    "GHSA-j7w6-vpvq-j3gm"
  ],
  "details": "Diffusers is the a library for  pretrained diffusion models. Prior to 0.38.0, diffusers 0.37.0 allows remote code execution without the trust_remote_code=True safeguard when loading pipelines from Hugging Face Hub repositories. The _resolve_custom_pipeline_and_cls function in pipeline_loading_utils.py performs string interpolation on the custom_pipeline parameter using f\"{custom_pipeline}.py\". When custom_pipeline is not supplied by the user, it defaults to None, which Python interpolates as the literal string \"None.py\". If an attacker publishes a Hub repository containing a file named None.py with a class that subclasses DiffusionPipeline, the file is automatically downloaded and executed during a standard DiffusionPipeline.from_pretrained() call with no additional keyword arguments. The trust_remote_code check in DiffusionPipeline.download() is bypassed because it evaluates custom_pipeline is not None as False (since the kwarg was never supplied), while the downstream code path that actually loads the module resolves the None value into a valid filename. An attacker can achieve silent arbitrary code execution by publishing a malicious model repository with a None.py file and a standard-looking model_index.json that references a legitimate pipeline class name, requiring only that a victim calls from_pretrained on the repository. This vulnerability is fixed in 0.38.0.",
  "id": "PYSEC-2026-41",
  "modified": "2026-05-20T09:18:56.729581Z",
  "published": "2026-05-14T17:16:23.500Z",
  "references": [
    {
      "type": "EVIDENCE",
      "url": "https://github.com/huggingface/diffusers/security/advisories/GHSA-j7w6-vpvq-j3gm"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}