CVE-2025-54365

fastapi-guard patch contains bypassable RegEx

State
Published
Severity
7.8 High
Published
Jul 23, 2025
Updated
Jul 24, 2025
Reserved
Jul 21, 2025

Read the record on cve.org

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 <script> 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.

Scores

CVSSScoreVectorSource
4.07.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:PGitHub_M

Weaknesses

  • CWE-20 Improper Input Validation
  • CWE-185 Incorrect Regular Expression

Affected Products

ProductVersions
fastapi-guardrennf93
  • >= 3.0.1, < 3.0.2Affected

References

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