{"cve":"CVE-2026-21871","nvd":{"published":"2026-01-08T10:15:55.300","modified":"2026-06-17T10:19:03.873","status":"Analyzed","description":"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 without page reload. However, if the URL argument is embedded into generated JavaScript without proper escaping, a crafted payload can break out of the intended string context and execute arbitrary JavaScript in the victim’s browser. Applications that do not pass untrusted input into ui.navigate.history.push/replace are not affected. This issue has been patched in version 3.5.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0","https://github.com/zauberzeug/nicegui/security/advisories/GHSA-7grm-h62g-5m97"],"products":["zauberzeug:nicegui"],"source":"nvd","synced_at":"2026-10-19T22:19:41.481987139+00:00"},"epss":{"cve":"CVE-2026-21871","score":0.00273,"percentile":0.19738,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-7grm-h62g-5m97","url":"https://osv.dev/vulnerability/GHSA-7grm-h62g-5m97","summary":"NiceGUI is vulnerable to XSS via Unescaped URL in ui.navigate.history.push() / replace()","modified":"2026-07-07T17:57:28.403615598Z","packages":[{"ecosystem":"PyPI","name":"nicegui","purl":"pkg:pypi/nicegui","ranges":[">=2.13.0 <3.5.0"],"fixed":["3.5.0"]}]},{"id":"PYSEC-2026-1698","url":"https://osv.dev/vulnerability/PYSEC-2026-1698","summary":"NiceGUI is vulnerable to XSS via Unescaped URL in ui.navigate.history.push() / replace()","modified":"2026-07-07T17:46:58.212425247Z","packages":[{"ecosystem":"PyPI","name":"nicegui","purl":"pkg:pypi/nicegui","ranges":[">=2.13.0 <3.5.0"],"fixed":["3.5.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}