{"id":"GHSA-9f46-5r25-5wfm","summary":"Time-of-check Time-of-use (TOCTOU) Race Condition in league/flysystem","details":"### Impact\n\nThe whitespace normalisation using in 1.x and 2.x removes any unicode whitespace. Under certain specific conditions this could potentially allow a malicious user to execute code remotely.\n\nThe conditions: \n\n- A user is allowed to supply the path or filename of an uploaded file.\n- The supplied path or filename is not checked against unicode chars.\n- The supplied pathname checked against an extension deny-list, not an allow-list.\n- The supplied path or filename contains a unicode whitespace char in the extension.\n- The uploaded file is stored in a directory that allows PHP code to be executed.\n\nGiven these conditions are met a user can upload and execute arbitrary code on the system under attack.\n\n### Patches\n\nThe unicode whitespace removal has been replaced with a rejection (exception).\n\nThe library has been patched in:\n- 1.x: https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32\n- 2.x: https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74\n\n### Workarounds\n\nFor 1.x users, upgrade to 1.1.4. For 2.x users, upgrade to 2.1.1.\n","aliases":["CVE-2021-32708"],"modified":"2026-05-07T05:00:20.898607291Z","published":"2021-06-29T03:13:28Z","database_specific":{"cwe_ids":["CWE-367"],"severity":"CRITICAL","github_reviewed":true,"github_reviewed_at":"2021-06-24T18:03:15Z","nvd_published_at":"2021-06-24T17:15:00Z"},"references":[{"type":"WEB","url":"https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32708"},{"type":"WEB","url":"https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74"},{"type":"WEB","url":"https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32"},{"type":"WEB","url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/league/flysystem/CVE-2021-32708.yaml"},{"type":"PACKAGE","url":"https://github.com/thephpleague/flysystem"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NWPTENBYKI2IG47GI4DHAACLNRLTWUR5"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RNZSWK4GOMJOOHKLZEOE5AQSLC4DNCRZ"},{"type":"WEB","url":"https://packagist.org/packages/league/flysystem"}],"affected":[{"package":{"name":"league/flysystem","ecosystem":"Packagist","purl":"pkg:composer/league/flysystem"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.1.4"}]}],"versions":["0.1.0","0.1.1","0.1.10","0.1.11","0.1.12","0.1.13","0.1.14","0.1.15","0.1.16","0.1.17","0.1.18","0.1.19","0.1.2","0.1.20","0.1.3","0.1.4","0.1.5","0.1.6","0.1.7","0.1.8","0.1.9","0.2.0","0.2.1","0.2.10","0.2.11","0.2.12","0.2.13","0.2.14","0.2.15","0.2.2","0.2.3","0.2.4","0.2.5","0.2.6","0.2.7","0.2.8","0.2.9","0.3.0","0.3.1","0.3.2","0.3.3","0.3.4","0.3.5","0.4.0","0.4.1","0.4.2","0.4.3","0.4.4","0.4.5","0.5.0","0.5.1","0.5.10","0.5.11","0.5.12","0.5.2","0.5.3","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.5.9","1.0.0","1.0.0-alpha1","1.0.1","1.0.10","1.0.11","1.0.12","1.0.13","1.0.14","1.0.15","1.0.16","1.0.17","1.0.18","1.0.19","1.0.2","1.0.20","1.0.21","1.0.22","1.0.23","1.0.24","1.0.25","1.0.26","1.0.27","1.0.28","1.0.29","1.0.3","1.0.30","1.0.31","1.0.32","1.0.33","1.0.34","1.0.35","1.0.36","1.0.37","1.0.38","1.0.39","1.0.4","1.0.40","1.0.41","1.0.42","1.0.43","1.0.44","1.0.45","1.0.46","1.0.47","1.0.48","1.0.49","1.0.5","1.0.50","1.0.51","1.0.52","1.0.53","1.0.54","1.0.55","1.0.56","1.0.57","1.0.58","1.0.59","1.0.6","1.0.60","1.0.61","1.0.62","1.0.63","1.0.64","1.0.65","1.0.66","1.0.67","1.0.68","1.0.69","1.0.7","1.0.70","1.0.8","1.0.9","1.1.0","1.1.1","1.1.2","1.1.3"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/06/GHSA-9f46-5r25-5wfm/GHSA-9f46-5r25-5wfm.json"}},{"package":{"name":"league/flysystem","ecosystem":"Packagist","purl":"pkg:composer/league/flysystem"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.0.0"},{"fixed":"2.1.1"}]}],"versions":["2.0.0","2.0.1","2.0.2","2.0.3","2.0.4","2.0.5","2.0.6","2.0.7","2.0.8","2.1.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/06/GHSA-9f46-5r25-5wfm/GHSA-9f46-5r25-5wfm.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}