{"id":"CVE-2020-26299","aliases":["EUVD-2021-0563","GHSA-pmw4-jgxx-pcq9"],"status":"published","title":"File System Bounds Escape","description":"ftp-srv is an open-source FTP server designed to be simple yet configurable. In ftp-srv before version 4.4.0 there is a path-traversal vulnerability. Clients of FTP servers utilizing ftp-srv hosted on Windows machines can escape the FTP user's defined root folder using the expected FTP commands, for example, CWD and UPDR. When windows separators exist within the path (`\\`), `path.resolve` leaves the upper pointers intact and allows the user to move beyond the root folder defined for that user. We did not take that into account when creating the path resolve function. The issue is patched in version 4.4.0 (commit 457b859450a37cba10ff3c431eb4aa67771122e3).","severity":{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.01886,"percentile":0.79667,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-22"],"published":"2021-02-10T18:10:19Z","modified":"2026-10-20T10:52:57Z","fixes":[{"ecosystem":"npm","package":"ftp-srv","fixed_in":["4.4.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"ftp-srv","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.4.0"}]}]},{"source":"osv","ecosystem":"npm","package":"ftp-srv","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.4.0"}]}]}],"products":[{"vendor":"autovance","product":"ftp-srv"},{"vendor":"ftp-srv_project","product":"ftp-srv"}],"references":[{"url":"https://www.npmjs.com/package/ftp-srv","tags":["x_refsource_MISC","x_transferred","Product","Third Party Advisory","advisory","web"]},{"url":"https://github.com/autovance/ftp-srv/security/advisories/GHSA-pmw4-jgxx-pcq9","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Third Party Advisory","evidence","web"]},{"url":"https://github.com/autovance/ftp-srv/issues/167","tags":["x_refsource_MISC","x_transferred","Exploit","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/autovance/ftp-srv/issues/225","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","evidence","web"]},{"url":"https://github.com/autovance/ftp-srv/pull/224","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/autovance/ftp-srv/commit/457b859450a37cba10ff3c431eb4aa67771122e3","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-26299","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-pmw4-jgxx-pcq9"}],"sources":{"cve":[{"id":"CVE-2020-26299","title":"File System Bounds Escape","description":"ftp-srv is an open-source FTP server designed to be simple yet configurable. In ftp-srv before version 4.4.0 there is a path-traversal vulnerability. Clients of FTP servers utilizing ftp-srv hosted on Windows machines can escape the FTP user's defined root folder using the expected FTP commands, for example, CWD and UPDR. When windows separators exist within the path (`\\`), `path.resolve` leaves the upper pointers intact and allows the user to move beyond the root folder defined for that user. We did not take that into account when creating the path resolve function. The issue is patched in version 4.4.0 (commit 457b859450a37cba10ff3c431eb4aa67771122e3).","status":"published","published":"2021-02-10T18:10:19Z","modified":"2024-08-04T15:56:04.494Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T14:35:45.763329Z"}],"euvd":[{"id":"EUVD-2021-0563","description":"ftp-srv is an open-source FTP server designed to be simple yet configurable. In ftp-srv before version 4.4.0 there is a path-traversal vulnerability. Clients of FTP servers utilizing ftp-srv hosted on Windows machines can escape the FTP user's defined root folder using the expected FTP commands, for example, CWD and UPDR. When windows separators exist within the path (`\\`), `path.resolve` leaves the upper pointers intact and allows the user to move beyond the root folder defined for that user. We did not take that into account when creating the path resolve function. The issue is patched in version 4.4.0 (commit 457b859450a37cba10ff3c431eb4aa67771122e3).","status":"published","published":"2021-02-10T18:10:19Z","modified":"2024-08-04T15:56:04Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-03T03:07:14.653267Z"}],"ghsa":[{"id":"GHSA-pmw4-jgxx-pcq9","title":"File System Bounds Escape","description":"### Impact\n\nClients of FTP servers utilizing `ftp-srv` hosted on Windows machines can escape the  FTP user's defined root folder using the expected FTP commands, for example, `CWD` and `UPDR`.\n\n### Background\n\nWhen windows separators exist within the path (`\\`), `path.resolve` leaves the upper pointers intact and allows the user to move beyond the root folder defined for that user. We did not take that into account when creating the path resolve function.\n\n![Screen Shot 2020-12-15 at 6 42 52 PM](https://user-images.githubusercontent.com/3375444/102293941-5a75fb80-3f05-11eb-9d71-0c190a8dcc75.png)\n\n### Patches\nNone at the moment.\n\n### Workarounds\nThere are no workarounds for windows servers. Hosting the server on a different OS mitigates the issue.\n\n### References\n\nIssues: \nhttps://github.com/autovance/ftp-srv/issues/167\nhttps://github.com/autovance/ftp-srv/issues/225\n\n### For more information\nIf you have any questions or comments about this advisory:\nOpen an issue at https://github.com/autovance/ftp-srv.\nPlease email us directly; security@autovance.com.","status":"published","published":"2021-02-10T18:11:34Z","modified":"2023-02-01T05:05:06Z","cwes":["CWE-22"],"updated_at":"2026-11-02T14:36:32.918681Z"}],"nvd":[{"id":"CVE-2020-26299","description":"ftp-srv is an open-source FTP server designed to be simple yet configurable. In ftp-srv before version 4.4.0 there is a path-traversal vulnerability. Clients of FTP servers utilizing ftp-srv hosted on Windows machines can escape the FTP user's defined root folder using the expected FTP commands, for example, CWD and UPDR. When windows separators exist within the path (`\\`), `path.resolve` leaves the upper pointers intact and allows the user to move beyond the root folder defined for that user. We did not take that into account when creating the path resolve function. The issue is patched in version 4.4.0 (commit 457b859450a37cba10ff3c431eb4aa67771122e3).","status":"published","published":"2021-02-10T18:15:12.703Z","modified":"2026-06-17T03:08:01.727Z","cvss":[{"version":"3.1","score":6.3,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":9.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","level":"critical","assessor":"primary"},{"version":"2.0","score":5.5,"vector":"AV:N/AC:L/Au:S/C:P/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-22"],"updated_at":"2026-11-02T14:06:34.188486Z"}],"osv":[{"id":"CVE-2020-26299","description":"ftp-srv is an open-source FTP server designed to be simple yet configurable. In ftp-srv before version 4.4.0 there is a path-traversal vulnerability. Clients of FTP servers utilizing ftp-srv hosted on Windows machines can escape the FTP user's defined root folder using the expected FTP commands, for example, CWD and UPDR. When windows separators exist within the path (`\\`), `path.resolve` leaves the upper pointers intact and allows the user to move beyond the root folder defined for that user. We did not take that into account when creating the path resolve function. The issue is patched in version 4.4.0 (commit 457b859450a37cba10ff3c431eb4aa67771122e3).","status":"published","published":"2021-02-10T18:15:12.703Z","modified":"2026-10-20T10:52:57.33840166Z","cvss":[{"version":"3.1","score":9.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T15:44:16.248747Z"},{"id":"GHSA-pmw4-jgxx-pcq9","title":"File System Bounds Escape","description":"### Impact\n\nClients of FTP servers utilizing `ftp-srv` hosted on Windows machines can escape the  FTP user's defined root folder using the expected FTP commands, for example, `CWD` and `UPDR`.\n\n### Background\n\nWhen windows separators exist within the path (`\\`), `path.resolve` leaves the upper pointers intact and allows the user to move beyond the root folder defined for that user. We did not take that into account when creating the path resolve function.\n\n![Screen Shot 2020-12-15 at 6 42 52 PM](https://user-images.githubusercontent.com/3375444/102293941-5a75fb80-3f05-11eb-9d71-0c190a8dcc75.png)\n\n### Patches\nNone at the moment.\n\n### Workarounds\nThere are no workarounds for windows servers. Hosting the server on a different OS mitigates the issue.\n\n### References\n\nIssues: \nhttps://github.com/autovance/ftp-srv/issues/167\nhttps://github.com/autovance/ftp-srv/issues/225\n\n### For more information\nIf you have any questions or comments about this advisory:\nOpen an issue at https://github.com/autovance/ftp-srv.\nPlease email us directly; security@autovance.com.","status":"published","published":"2021-02-10T18:11:34Z","modified":"2026-07-08T06:00:48.447764796Z","cwes":["CWE-22"],"updated_at":"2026-11-02T15:46:53.244788Z"}]}}