CVE-2026-33332 MEDIUM

CVE-2026-33332: NiceGUI's unvalidated chunk size parameter in media routes can cause memory exhaustion

Vendor Zauberzeug
Product nicegui
Weakness CWE-20 · Input validation
Published March 24, 2026
Last update March 25, 2026

CVSS base score

6.9/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS 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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 24, 2026 CVE published
March 25, 2026 Record updated