CVE-2025-53354Public exploitNetwork attack vector

Reflected XSS via unsanitized HTML rendering

Published Oct 3, 2025 · Updated Oct 3, 2025

Reflected XSS in NiceGUI before 3.0.0 allows remote attackers to execute JavaScript in a user's browser through unescaped input. The ui.html() element writes content into the DOM through innerHTML without sanitization, and ui.chat_message() likewise passes HTML-mode text to Html. Exploitation requires an application to pass attacker-controlled content to either API and a user to render it; the script then runs in that application's browser origin.

CVSS severity6.1
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in NiceGUI before 3.0.0 allows remote attackers to execute JavaScript in a user's browser through unescaped input. The ui.html() element writes content into the DOM through innerHTML without sanitization, and ui.chat_message() likewise passes HTML-mode text to Html. Exploitation requires an application to pass attacker-controlled content to either API and a user to render it; the script then runs in that application's browser origin.

The record

CVE
CVE-2025-53354
Published
Oct 3, 2025
Updated
Oct 3, 2025
Vendor
Zauberzeug
Product
NiceGUI
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zauberzeug · NiceGUIversion=< 3.0.0

Published CVSS scores

6.1GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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