NiceGUI apps are vulnerable to XSS which uses `ui.sub_pages` and render arbitrary user-provided links
Priority MEDIUM 60CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.
Summary
NiceGUI is a Python-based UI framework. From versions 2.22.0 to 3.4.1, an unsafe implementation in the click event listener used by ui.sub_pages, combined with attacker-controlled link rendering on the page, causes XSS when the user actively clicks on the link. This issue has been patched in version 3.5.0.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00271 19th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed nicegui (zauberzeug): 3.5.0nicegui (PyPI): 3.5.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| zauberzeug | nicegui | 2.22.0 to before 3.5.0 | 3.5.0 | Patch available | CNA |
| — | nicegui (PyPI) | 2.22.0 to before 3.5.0 | 3.5.0 | Patch available | GHSA-m7j5-rq9j-6jj9 |
- nicegui Vendorzauberzeug Affected 2.22.0 to before 3.5.0 Fixed in 3.5.0 Patch available CNA
- nicegui (PyPI) Vendor— Affected 2.22.0 to before 3.5.0 Fixed in 3.5.0 Patch available GHSA-m7j5-rq9j-6jj9
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:zauberzeug:nicegui:*:*:*:*:*:*:*:* | 2.22.0 to before 3.5.0 | Vulnerable | zauberzeug |
- cpe:2.3:a:zauberzeug:nicegui:*:*:*:*:*:*:*:* Versions 2.22.0 to before 3.5.0 Vulnerable ·zauberzeug
Remediation
- Fix · CNA nicegui (zauberzeug) Fixed in 3.5.0
- Fix · GHSA-m7j5-rq9j-6jj9 nicegui (PyPI) Fixed in 3.5.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-21872
- 2026-10-03 Alias added: GHSA-m7j5-rq9j-6jj9
References
More zauberzeug Nicegui vulnerabilities
- TI-2025-41029 NiceGUI Path Traversal Vulnerability in app.add_media_files() Allows Arbitrary File Reading CVSS 3.1HIGH 7.5
- TI-2026-17574 Zero-click XSS in all NiceGUI apps which uses `ui.sub_pages` CVSS 3.1HIGH 7.2
- TI-2026-17575 NiceGUI has Redis connection leak via tab storage causes service degradation CVSS 3.1MEDIUM 5.3
- TI-2026-17572 NiceGUI is vulnerable to XSS via Unescaped URL in ui.navigate.history.push() / replace() CVSS 3.1MEDIUM 6.1
- TI-2025-40897 NiceGUI Stored/Reflected XSS in ui.interactive_image via unsanitized SVG content CVSS 3.1MEDIUM 6.1
- TI-2025-40896 NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection CVSS 3.1MEDIUM 6.1
Sources
- CVE-2026-21872 · CVE Program
- CVE-2026-21872 · NVD
- FIRST EPSS
- GHSA-m7j5-rq9j-6jj9 · GitHub Advisory Database · CC BY 4.0
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