CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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5DescriptionNVD
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.
AnalysisAI
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.
Technical ContextAI
This vulnerability is classified as Inefficient Regular Expression Complexity (ReDoS) (CWE-1333).
RemediationAI
A vendor patch is available. Apply it as soon as possible and verify the fix.
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External POC / Exploit Code
Leaving vuln.today
EUVD-2025-20307
GHSA-j47q-rc62-w448