CVE-2025-53539
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductFastapi-guard Fastapi Guard
PublishedJul 7, 2025
First seenJul 7, 2025
Weakness typeCWE-1333CWE-1333
How to fix
Update
- fastapi-guard fastapi_guard3.0.1 or later
- fastapi-guard3.0.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| fastapi-guard fastapi_guard | v < 3.0.1 | 3.0.1 |
| fastapi-guardPyPI | v < 3.0.1 | 3.0.1 |
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