Cross-site Scripting (XSS)

Overview nicegui is a Create web-based user interfaces with Python. The nice way. Affected versions of this package are vulnerable to Cross-site Scripting XSS via the ui.navigate.history.push or ui.navigate.history.replace functions. An attacker can execute arbitrary JavaScript in the victim's...

NiceGUI is vulnerable to XSS via Unescaped URL in ui.navigate.history.push() / replace()

Summary XSS risk exists in NiceGUI when developers pass attacker-controlled strings into ui.navigate.history.push or ui.navigate.history.replace. These helpers are documented as History API wrappers for updating the browser URL without page reload. However, if the URL argument is embedded into...

CVE-2026-21871

NiceGUI is a Python-based UI framework. From versions 2.13.0 to 3.4.1, there is a XSS risk in NiceGUI when developers pass attacker-controlled strings into ui.navigate.history.push or ui.navigate.history.replace. These helpers are documented as History API wrappers for updating the browser URL...

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.subpages 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...

CVE-2026-21872

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.subpages, 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 versi...

CVE-2026-21874

NiceGUI is a Python-based UI framework. From versions v2.10.0 to 3.4.1, an unauthenticated attacker can exhaust Redis connections by repeatedly opening and closing browser tabs on any NiceGUI application using Redis-backed storage. Connections are never released, leading to service degradation wh...

CVE-2026-21874 NiceGUI has Redis connection leak via tab storage causes service degradation

NiceGUI is a Python-based UI framework. From versions v2.10.0 to 3.4.1, an unauthenticated attacker can exhaust Redis connections by repeatedly opening and closing browser tabs on any NiceGUI application using Redis-backed storage. Connections are never released, leading to service degradation wh...

CVE-2026-21874 NiceGUI has Redis connection leak via tab storage causes service degradation

NiceGUI is a Python-based UI framework. From versions v2.10.0 to 3.4.1, an unauthenticated attacker can exhaust Redis connections by repeatedly opening and closing browser tabs on any NiceGUI application using Redis-backed storage. Connections are never released, leading to service degradation wh...

CVE-2026-21874

CVE-2026-21874 affects NiceGUI versions 2.10.0 through 3.4.1 where an unauthenticated attacker can exhaust Redis connections by repeatedly opening/closing browser tabs using Redis-backed storage. This tab-storage leak prevents Redis connections from being released, causing Redis to reach its max ...

CVE-2026-21874 NiceGUI has Redis connection leak via tab storage causes service degradation

NiceGUI is a Python-based UI framework. From versions v2.10.0 to 3.4.1, an unauthenticated attacker can exhaust Redis connections by repeatedly opening and closing browser tabs on any NiceGUI application using Redis-backed storage. Connections are never released, leading to service degradation wh...

EUVD-2026-1474

NiceGUI is a Python-based UI framework. From versions v2.10.0 to 3.4.1, an unauthenticated attacker can exhaust Redis connections by repeatedly opening and closing browser tabs on any NiceGUI application using Redis-backed storage. Connections are never released, leading to service degradation wh...

EUVD-2026-1475

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.subpages 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...

CVE-2026-21873

NiceGUI (Python UI framework) has a cross-site scripting risk in versions 2.22.0–3.4.1 due to an unsafe pushstate listener in ui.sub_pages that lets an attacker manipulate the URL fragment via an iframe. The issue is exploitable without user interaction and affects pages embeddable in iframes. A ...

CVE-2026-21873 Zero-click XSS in all NiceGUI apps which uses `ui.sub_pages`

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.subpages 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...

CVE-2026-21873 Zero-click XSS in all NiceGUI apps which uses `ui.sub_pages`

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.subpages 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...

CVE-2026-21873 Zero-click XSS in all NiceGUI apps which uses `ui.sub_pages`

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.subpages 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...

CVE-2026-21872 NiceGUI apps are vulnerable to XSS which uses `ui.sub_pages` and render arbitrary user-provided links

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.subpages, 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 versi...

EUVD-2026-1477

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.subpages, 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 versi...

CVE-2026-21872 NiceGUI apps are vulnerable to XSS which uses `ui.sub_pages` and render arbitrary user-provided links

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.subpages, 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 versi...

CVE-2026-21872

NiceGUI (Python UI framework) versions 2.22.0–3.4.1 are affected by an XSS vulnerability caused by an unsafe implementation in the click event listener used by ui.sub_pages, combined with attacker-controlled link rendering on the page. The issue triggers when a user actively clicks a crafted link...