{"cve":"CVE-2026-39844","nvd":{"published":"2026-04-08T21:16:59.883","modified":"2026-07-24T21:10:00.143","status":"Analyzed","description":"NiceGUI is a Python-based UI framework. Prior to 3.10.0, Since PurePosixPath only recognizes forward slashes (/) as path separators, an attacker can bypass this sanitization on Windows by using backslashes (\\) in the upload filename. Applications that construct file paths using file.name (a pattern demonstrated in NiceGUI's bundled examples) are vulnerable to arbitrary file write on Windows. This vulnerability is fixed in 3.10.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":["CWE-22"],"references":["https://github.com/zauberzeug/nicegui/commit/d38a702e3af2da5b0708f689be8d71413fc77056","https://github.com/zauberzeug/nicegui/releases/tag/v3.10.0","https://github.com/zauberzeug/nicegui/security/advisories/GHSA-w8wv-vfpc-hw2w"],"products":["zauberzeug:nicegui"],"source":"nvd","synced_at":"2026-10-19T22:28:59.047572785+00:00"},"epss":{"cve":"CVE-2026-39844","score":0.00371,"percentile":0.31043,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-w8wv-vfpc-hw2w","url":"https://osv.dev/vulnerability/GHSA-w8wv-vfpc-hw2w","summary":"NiceGUI: Upload filename sanitization bypass via backslashes allows path traversal on Windows","modified":"2026-07-13T07:26:38.482689138Z","packages":[{"ecosystem":"PyPI","name":"nicegui","purl":"pkg:pypi/nicegui","ranges":["<3.10.0"],"fixed":["3.10.0"]}]},{"id":"PYSEC-2026-2234","url":"https://osv.dev/vulnerability/PYSEC-2026-2234","summary":"","modified":"2026-07-13T07:15:35.271485695Z","packages":[{"ecosystem":"PyPI","name":"nicegui","purl":"pkg:pypi/nicegui","ranges":["<3.10.0"],"fixed":["3.10.0"]}]}],"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."]}