CVE-2026-21873 — HIGH (7.2)

Q: How severe is CVE-2026-21873?

CVE-2026-21873 has been rated HIGH with a CVSS base score of 7.2/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2026-21873?

Check the references section above for vendor advisories and patch information. Affected products include: Zauberzeug Nicegui.

Vulnerability 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 Score

7.2

HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality

LOW

Integrity

LOW

Availability

NONE

Affected Products

Vendor	Product	Versions
Zauberzeug	Nicegui	>= 2.22.0, < 3.5.0

Related Weaknesses (CWE)

CWE-79

References

https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0Release Notes
https://github.com/zauberzeug/nicegui/security/advisories/GHSA-mhpg-c27v-6mxrExploitVendor Advisory

FAQ

What is CVE-2026-21873?

CVE-2026-21873 is a vulnerability with a CVSS score of 7.2 (HIGH). 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 ident...

How severe is CVE-2026-21873?

CVE-2026-21873 has been rated HIGH with a CVSS base score of 7.2/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-21873?

Check the references section above for vendor advisories and patch information. Affected products include: Zauberzeug Nicegui.