MAL-2026-4750

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/withdrawn/pypi/fastapi/MAL-2026-4750.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-4750
Withdrawn
2026-05-26T13:04:03Z
Published
2026-05-23T19:14:13Z
Modified
2026-05-27T00:32:10Z
Summary
Malicious code in fastapi (PyPI)
Details

-= Per source details. Do not edit below this line.=-

Source: amazon-inspector (a753fd569a7bb908b7cdf82fe0228dc0e24dcc253b67993af5dd5c30b61f4411)

This release of fastapi 0.136.3 modifies pyproject.toml and PKG-INFO to add an undocumented dependency 'fastar>=0.9.0' to the [project.optional-dependencies] standard group (pyproject.toml line 67: "fastar >= 0.9.0",; PKG-INFO line 47: Requires-Dist: fastar>=0.9.0; extra == "standard"). The README documents every other dependency in the [standard] group (httpx, jinja2, python-multipart, uvicorn, fastapi-cli, email-validator, pydantic-settings, pydantic-extra-types) but does not mention 'fastar'. Because the documented recommended install command is pip install "fastapi[standard]", every user following the official documentation silently pulls the unrelated 'fastar' package onto their developer or CI machine. The name 'fastar' is a typosquat-shaped substitution against 'fastapi'/'fastapi-*' namespaces, and its insertion into the canonical install path of one of PyPI's most-installed web frameworks constitutes a dependency-confusion / namespace-abuse vector regardless of what 'fastar' currently contains. Whoever controls 'fastar' on PyPI gains code execution at install time on a very large user base.

Database specific 
{
    "malicious-packages-origins": [
        {
            "id": "IN-MAL-2026-004380",
            "import_time": "2026-05-26T05:52:29.184410944Z",
            "modified_time": "2026-05-23T19:14:13Z",
            "sha256": "a753fd569a7bb908b7cdf82fe0228dc0e24dcc253b67993af5dd5c30b61f4411",
            "source": "amazon-inspector",
            "versions": [
                "0.136.3"
            ]
        }
    ]
}
References
Credits

Affected packages

PyPI / fastapi

Package

Name
fastapi
View open source insights on deps.dev
Purl
pkg:pypi/fastapi

Affected ranges

Affected versions

0.*
0.136.3

Database specific

cwes 
[
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    }
]
indicators 
{
    "evidence_files": [
        {
            "path": "pyproject.toml",
            "sha256": "ea0180f65c21d699804d214af7461e2fb07d6178283e2a2767490bca95f5a14e",
            "tlsh": "cd22ef67d4ac9eb13b8170e9c188134189956023bd06358c77cd814e9f4eaef937da3e"
        }
    ],
    "package_integrity": [
        {
            "filename": "fastapi-0.136.3-py3-none-any.whl",
            "hashes": {
                "blake2b_256": "e08245359b62a067409bd929ae8a56b8ed13e5a8c8a61194b3c236920999ab83",
                "md5": "51f97b50ece91fc6f78e673f55ed0c4e",
                "sha256": "3d2a69bdf04b7e9f3afa292c3bc7a98816bbfafa10bc9b45f3f3700d2f761620"
            }
        },
        {
            "filename": "fastapi-0.136.3.tar.gz",
            "hashes": {
                "blake2b_256": "812dff8d91d7b564d464629a0fd50a4489c97fcb836ac230bf3a7269232a9b1f",
                "md5": "5e22f728ab9ea5c99a29a0137b4b8b55",
                "sha256": "e487fae93ad408e6f47641ee4dfe389864fd7bec92e547ea8498fc13f43e83ab"
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/withdrawn/pypi/fastapi/MAL-2026-4750.json"