CVE-2026-21873

6.1 mediumEPSS 0.3%

Medium (6.1) in zauberzeug nicegui. EPSS 0.3% chance of exploitation in the next 30 days. Fixed in nicegui 3.5.0.

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.

Severity

CVSS 3.1

6.1 medium

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

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 17% of CVEs (scores of 2026-10-31)
CWE: CWE-79
Published: 2026-01-08
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

zauberzeug:nicegui

Packages (OSV)

Advisory	Ecosystem	Package	Affected	Fixed in
GHSA-mhpg-c27v-6mxr	PyPI	nicegui	>=2.22.0 <3.5.0	3.5.0
PYSEC-2026-1702	PyPI	nicegui	>=2.22.0 <3.5.0	3.5.0

References

https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0
https://github.com/zauberzeug/nicegui/security/advisories/GHSA-mhpg-c27v-6mxr

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