Description
FastAPI Guard is a security library for FastAPI that provides middleware to control IPs, log requests, and detect penetration attempts. fastapi-guard's penetration attempts detection uses regex to scan incoming requests. However, some of the regex patterns used in detection are extremely inefficient and can cause polynomial complexity backtracks when handling specially crafted inputs. This vulnerability is fixed in 3.0.1.
References (2)
Core 2
Core References
Exploit, Vendor Advisory x_refsource_confirm
https://github.com/rennf93/fastapi-guard/security/advisories/GHSA-j47q-rc62-w448
Scores
CVSS v3
7.5
EPSS
0.0042
EPSS Percentile
33.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
partial
Details
CWE
CWE-1333
Status
published
Products (2)
fastapi-guard/fastapi_guard
< 3.0.1
pypi/fastapi-guard
0 - 3.0.1PyPI
Published
Jul 07, 2025
Tracked Since
Feb 18, 2026