CVE-2026-45554CWE-248CWE-770

NiceGUI: Unauthenticated log-flood DoS via trailing slash on ESM and per-component resource routes

Medium · published June 2, 2026

CVSS v3.1
5.3
EPSS
1%
Percentile
48.0
In the wild
Unconfirmed
What it is

NiceGUI is a Python-based UI framework. Prior to version 3.12.0, two FastAPI routes that serve per-component static assets in NiceGUI accept a sub-path parameter that may resolve to a directory rather than a file. Requests that resolve to a directory raise an unhandled RuntimeError inside Starlette's FileResponse, which Uvicorn writes to the server log as a full traceback. Because the routes are reachable without authentication, a remote attacker can amplify log volume and consume disk and log-pipeline capacity on any publicly reachable NiceGUI server. This issue has been patched in version 3.12.0.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00600 · 48.0th percentile
Weaknesses
CWE-248 · Uncaught Exception; CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-06-02T15:35Z
EPSS history
Timeline
  • 02 JUN 15:35Z
    NiceGUI: Unauthenticated log-flood DoS via trailing slash on ESM and per-component resource routes
    cvelistv5