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NOTICE UPDATED - April, 25th 2024

NIST has updated the NVD program announcement page with additional information regarding recent concerns and the temporary delays in enrichment efforts.

CVE-2021-32677 Detail

Description

FastAPI is a web framework for building APIs with Python 3.6+ based on standard Python type hints. FastAPI versions lower than 0.65.2 that used cookies for authentication in path operations that received JSON payloads sent by browsers were vulnerable to a Cross-Site Request Forgery (CSRF) attack. In versions lower than 0.65.2, FastAPI would try to read the request payload as JSON even if the content-type header sent was not set to application/json or a compatible JSON media type (e.g. application/geo+json). A request with a content type of text/plain containing JSON data would be accepted and the JSON data would be extracted. Requests with content type text/plain are exempt from CORS preflights, for being considered Simple requests. The browser will execute them right away including cookies, and the text content could be a JSON string that would be parsed and accepted by the FastAPI application. This is fixed in FastAPI 0.65.2. The request data is now parsed as JSON only if the content-type header is application/json or another JSON compatible media type like application/geo+json. It's best to upgrade to the latest FastAPI, but if updating is not possible then a middleware or a dependency that checks the content-type header and aborts the request if it is not application/json or another JSON compatible content type can act as a mitigating workaround.


Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  8.1 HIGH
Vector:  CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  8.2 HIGH
Vector:  CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/tiangolo/fastapi/commit/fa7e3c996edf2d5482fff8f9d890ac2390dede4d Patch  Third Party Advisory 
https://github.com/tiangolo/fastapi/security/advisories/GHSA-8h2j-cgx8-6xv7 Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MATAWX25TYKNEKLDMKWNLYDB34UWTROA/

Weakness Enumeration

CWE-ID CWE Name Source
CWE-352 Cross-Site Request Forgery (CSRF) Provider acceptance level GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Denotes Vulnerable Software
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Change History

4 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-32677
NVD Published Date:
06/09/2021
NVD Last Modified:
02/12/2024
Source:
GitHub, Inc.