Vulnerability details
CVE-2026-21873
zauberzeug nicegui
Zero-click XSS in all NiceGUI apps which uses `ui.sub_pages`
CVSS 3.1
7.2High
Official description
NiceGUI is a Python-based UI framework. From versions 2.22.0 to 3.4.1, an unsafe implementation in the pushstate event listener used by ui.sub_pages allows an attacker to manipulate the fragment identifier of the URL, which they can do despite being cross-site, using an iframe. This issue has been patched in version 3.5.0.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.2High | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| zauberzeug | nicegui | >= 2.22.0, < 3.5.0 | CVEProject cvelistV5 (CNA) |
References and advisories
2- https://github.com/zauberzeug/nicegui/security/advisories/GHSA-mhpg-c27v-6mxr x_refsource_CONFIRM
- https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0 x_refsource_MISC
Kolun on Telegram @kolunsec
Exploited CVEs, key news and a daily digest
Alerts for this product's next CVEsFollow the product to get new vulnerabilities on Telegram.
Details
- Published
- 2026-01-08
- Last updated
- 2026-01-08
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
0.26%
Probability of exploitation in 30 days
17.8%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- Proof of concept
- Technical impact
- Partial
Weaknesses (CWE)
- CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')