{"id":"PYSEC-2026-3428","summary":"WsgiDAV encoded dot segments can escape filesystem share roots","details":"### Impact\nWsgiDAV 4.3.3 can allow a WebDAV request path containing an encoded parent-directory segment to escape the configured filesystem share root in a specific path layout.\n\n### Patches\nThe issue is fixed with version 4.3.4.\n\n### Preconditions\n\nThe practical impact depends on the deployment.\n\nThe deployment uses a filesystem-backed WsgiDAV share.\n\nThe attacker can send WebDAV requests accepted by that share. This may be an anonymous share or an authenticated WebDAV user. This is not an authentication bypass.\n\n### Details\n\nThe issue is in `FilesystemProvider._loc_to_file_path()`. The method builds a candidate path with `os.path.abspath(os.path.join(root_path, *path_parts))`, then checks containment with `file_path.startswith(root_path)`. This is not path-boundary aware. For example, if the configured share root is `/tmp/share`, a resolved sibling path such as `/tmp/share_evil/secret.txt` still starts with the string `/tmp/share`.\n\nIn a local proof, this allowed GET, PUT, and DELETE requests to operate on files outside the configured share root.\n\nThe WSGI/server layer forwards the encoded dot segment to WsgiDAV's PATH_INFO. The local proof used `/%2e%2e/...`, which wsgiref passed through as `/../...`.\n\nA sibling or neighboring path exists whose absolute path starts with the configured root path string, such as `/tmp/share` and `/tmp/share_evil`.\n\nThe WsgiDAV process has OS permissions for the outside path.","aliases":["CVE-2026-48099","GHSA-wxq4-cc2q-338q"],"modified":"2026-07-13T16:33:27.849732925Z","published":"2026-07-13T15:46:16.868348Z","references":[{"type":"WEB","url":"https://github.com/mar10/wsgidav/security/advisories/GHSA-wxq4-cc2q-338q"},{"type":"WEB","url":"https://github.com/mar10/wsgidav/commit/f894ed8656d7bdd7438ab8148c5a02546cb15183"},{"type":"PACKAGE","url":"https://github.com/mar10/wsgidav"},{"type":"PACKAGE","url":"https://pypi.org/project/wsgidav"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-wxq4-cc2q-338q"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48099"}],"affected":[{"package":{"name":"wsgidav","ecosystem":"PyPI","purl":"pkg:pypi/wsgidav"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.3.4"}]}],"versions":["0.4.0b1","0.4.0b2","0.5.0","1.0.0","1.1.0","1.2.0","1.3.0","2.0.0","2.0.1","2.1.0","2.2.1","2.2.2","2.2.3","2.2.4","2.3.0","2.4.0","2.4.1","3.0.0","3.0.0a1","3.0.0a2","3.0.0a3","3.0.0a4","3.0.0a5","3.0.0a6","3.0.0a7","3.0.1","3.0.2","3.0.3","3.0.5a2","3.0.5a3","3.1.0","3.1.1","4.0.0","4.0.0a2","4.0.1","4.0.2","4.1.0","4.2.0","4.3.0","4.3.1","4.3.2","4.3.3"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/wsgidav/PYSEC-2026-3428.yaml"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L"}]}