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Medium · 6.9 CVE-2025-53539 EUVD-2025-20307GHSA-j47q-rc62-w448PYSEC-2026-1359

ReDoS in fastapi-guard's penetration attempts detector

Published Jul 7, 2025 · Updated Jul 7, 2025 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
rennf93 fastapi-guard < 3.0.1 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI fastapi-guard < 3.0.1 3.0.1 GHSA-j47q-rc62-w448

References