MAL-2026-4750
Malicious code in fastapi (PyPI)
- Severity
- Not rated yet
- No source has published a CVSS score yet
- Exploit chance (EPSS)
- —
- No score published
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- —
- Not classified
- Fix
- None yet
- No fixed version published
Description
-= 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.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| fastapi | 1 listed versions | No fix yet |
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
References
Packages
Timeline
- Published
- Withdrawn
- Last updated by the source
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| PYSEC-2024-38 python-multipart vulnerable to Content-Type Header ReDoS | High | Also affects fastapi |
| GHSA-8h2j-cgx8-6xv7 Cross-Site Request Forgery (CSRF) in FastAPI | High | Also affects fastapi |
Credits: Amazon Inspector
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