CVE-2025-53354VulnerabilityPublished 3 Oct 2025

CVE-2025-53354: zauberzeug nicegui · Cross-site Scripting

Affects zauberzeug niceguiSource CVE Database V5

Not known to be exploited · CVSS 6.1 Medium : upgrade to 3.0.0 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

6.1Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.0.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade zauberzeug nicegui to 3.0.0.

Affected software

Product	Affected	Fixed in
zauberzeug nicegui	Affected <3.0.0	Fixed in 3.0.0

AI-suggested

European organizations should immediately upgrade all NiceGUI deployments to version 3.0.0 or later, where the vulnerability is fixed. Until upgrades are completed, developers must audit their applications to identify any use of ui.html() or ui.chat_message components that render user input without proper escaping or sanitization. Input validation and output encoding should be implemented rigorously to neutralize any HTML or JavaScript content before rendering. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. Additionally, security teams should monitor web application logs for suspicious input patterns and user behavior indicative of XSS attempts. User education on phishing and suspicious links can reduce the risk from social engineering vectors. Finally, incorporate automated security testing tools that detect XSS vulnerabilities during development and deployment cycles to prevent recurrence.

Description

NiceGUI is a Python-based UI framework. Versions 2.24.2 and below are at risk for Cross-Site Scripting (XSS) when developers render unescaped user input into the DOM using ui.html(). NiceGUI did not enforce HTML or JavaScript sanitization, so applications that directly combine components like ui.input() with ui.html() or ui.chat_message with HTML content without escaping may allow attackers to execute arbitrary JavaScript in the user’s browser. Applications that do not pass untrusted input into ui.html() are not affected. This issue is fixed in version 3.0.0.

Impact

For European organizations using NiceGUI versions prior to 3.0.0, this vulnerability poses a risk of client-side script injection leading to session hijacking, credential theft, defacement, or unauthorized actions performed on behalf of users. Since NiceGUI is a UI framework, the impact depends heavily on how developers use it; applications that directly render unescaped user input into the DOM are vulnerable. The confidentiality and integrity of user data can be compromised, potentially exposing sensitive information or enabling further attacks such as phishing or lateral movement within internal networks. The vulnerability does not affect availability directly but can undermine user trust and compliance with data protection regulations such as GDPR if personal data is exposed. European organizations in sectors with high web application usage, such as finance, healthcare, and government, may face reputational damage and regulatory penalties if exploited. The requirement for user interaction limits automated exploitation but targeted attacks against employees or customers remain feasible.

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Oct 2025, 19:35 UTC

WeaknessesCWE-79

Technical details

References

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