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HIGH · 7.5

CVE-2025-53539

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 sca...

Vulnerability 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.

CVSS Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
Fastapi-GuardFastapi Guard< 3.0.1

Related Weaknesses (CWE)

CWE-1333

References

FAQ

What is CVE-2025-53539?

CVE-2025-53539 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 sca...

How severe is CVE-2025-53539?

CVE-2025-53539 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2025-53539?

Check the references section above for vendor advisories and patch information. Affected products include: Fastapi-Guard Fastapi Guard.