CVE-2026-33332

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

HIGH
7.5
CVSS Score
Published: March 24, 2026 at 07:20 PM UTC
Updated: June 17, 2026 at 10:37 AM UTC
1 product affected across 1 vendorNicegui

Using nicegui by zauberzeug?

Get instant alerts when new vulnerabilities affect nicegui - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.9.0
Affected range stops below 3.9.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_CONFIRMMitigationVendor Advisory
Source: cverecord
https://github.com/zauberzeug/nicegui/security/advisories/GHSA-w5g8-5849-vj76
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/zauberzeug/nicegui/releases/tag/v3.9.0

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-20CWE-770

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card