CVE-2021-32677

Sažetak

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.

Reference

CVSS

Base:	5.8
Impact:	4.9
Exploitability:	8.6

Pristup

Vektor	Složenost	Autentikacija
NETWORK	MEDIUM	NONE

Impact

Povjerljivost	Cjelovitost	Dostupnost
PARTIAL	PARTIAL	NONE

CVSS vektor

AV:N/AC:M/Au:N/C:P/I:P/A:N

Zadnje važnije ažuriranje

12-02-2024 - 20:04

Objavljeno

09-06-2021 - 18:15