CVE-2026-33332CWE-20CWE-770

NiceGUI's unvalidated chunk size parameter in media routes can cause memory exhaustion

Medium · published March 24, 2026

CVSS v4.0
6.9
EPSS
1%
Percentile
53.3
In the wild
Unconfirmed
What it is

NiceGUI is a Python-based UI framework. Prior to version 3.9.0, NiceGUI's app.add_media_file() and app.add_media_files() media routes accept a user-controlled query parameter that influences how files are read during streaming. The parameter is passed to the range-response implementation without validation, allowing an attacker to bypass chunked streaming and force the server to load entire files into memory at once. With large media files and concurrent requests, this can lead to excessive memory consumption, degraded performance, or denial of service. This issue has been patched in version 3.9.0.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
EPSS
0.00719 · 53.3th percentile
Weaknesses
CWE-20 · Improper Input Validation; CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-03-24T19:20Z
EPSS history
Timeline
  • 24 MAR 19:20Z
    NiceGUI's unvalidated chunk size parameter in media routes can cause memory exhaustion
    cvelistv5