CVE-2026-21873

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.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTNIST
7.2 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
GitHub_MCNA
7.2 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
CISA-ADPADP
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Base Score
CVSS 3.x
EPSS Score
Percentile: 7%
Common Weakness Enumeration
References
https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0
https://github.com/zauberzeug/nicegui/security/advisories/GHSA-mhpg-c27v-6mxr