CVE-2025-54365 – Fastapi-Guard Regular Expression ReDoS Bypass

The following table lists the changes that have been made to the
CVE-2025-54365 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution
of a vulnerability, and for identifying the most recent changes that may
impact the vulnerability’s severity, exploitability, or other characteristics.

  • New CVE Received
    by [email protected]

    Jul. 23, 2025

    Action Type Old Value New Value
    Added Description fastapi-guard is a security library for FastAPI that provides middleware to control IPs, log requests, detect penetration attempts and more. In version 3.0.1, the regular expression patched to mitigate the ReDoS vulnerability by limiting the length of string fails to catch inputs that exceed this limit. This type of patch fails to detect cases in which the string representing the attributes of a tag exceeds 100 characters. As a result, most of the regex patterns present in version 3.0.1 can be bypassed. This is fixed in version 3.0.2.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CWE CWE-20
    Added CWE CWE-185
    Added Reference https://github.com/rennf93/fastapi-guard/commit/0829292c322d33dc14ab00c5451c5c138148035a
    Added Reference https://github.com/rennf93/fastapi-guard/commit/d9d50e8130b7b434cdc1b001b8cfd03a06729f7f
    Added Reference https://github.com/rennf93/fastapi-guard/security/advisories/GHSA-rrf6-pxg8-684g
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