{"cve":"CVE-2025-66469","nvd":{"published":"2025-12-09T00:15:49.330","modified":"2026-10-19T19:10:00.130","status":"Analyzed","description":"NiceGUI is a Python-based UI framework. Versions 3.3.1 and below are vulnerable to Reflected XSS through its ui.add_css, ui.add_scss, and ui.add_sass functions. The functions lack proper sanitization or encoding for the JavaScript context they generate. An attacker can break out of the intended <style> or <script> tags by injecting closing tags (e.g., </style> or </script>), allowing for the execution of arbitrary JavaScript. This issue is fixed in version 3.4.0.","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/commit/a8fd25b7d5e23afb1952d0f60a1940e18b5f1ca8","https://github.com/zauberzeug/nicegui/security/advisories/GHSA-72qc-wxch-74mg","https://github.com/zauberzeug/nicegui/security/advisories/GHSA-72qc-wxch-74mg"],"products":["zauberzeug:nicegui"],"source":"nvd","synced_at":"2026-10-19T22:16:40.427100871+00:00"},"epss":{"cve":"CVE-2025-66469","score":0.00275,"percentile":0.19699,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-72qc-wxch-74mg","url":"https://osv.dev/vulnerability/GHSA-72qc-wxch-74mg","summary":"NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection","modified":"2026-07-07T17:56:17.014157648Z","packages":[{"ecosystem":"PyPI","name":"nicegui","purl":"pkg:pypi/nicegui","ranges":["<3.4.0"],"fixed":["3.4.0"]}]},{"id":"PYSEC-2026-1697","url":"https://osv.dev/vulnerability/PYSEC-2026-1697","summary":"NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection","modified":"2026-07-07T17:46:58.150165705Z","packages":[{"ecosystem":"PyPI","name":"nicegui","purl":"pkg:pypi/nicegui","ranges":["<3.4.0"],"fixed":["3.4.0"]}]}],"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."]}