{"id":"CVE-2026-105420","kind":"vulnerability","aliases":["CVE-2026-105420"],"related":[],"title":"Wing FTP Server: user base folder check lets admins write files outside it","description":"Wing FTP Server does not verify user's base folder. An attacker with admin privileges can add user directories via scripts, allowing the added directories to escape the base folder. This allows the attacker to write files on the system and can lead to remote code execution with process owner privileges.Critically, since the installation guide mentions running the command with `sudo`, the files are created as “root.”\n\n\n\n\nThis issue was fixed in version 8.2.6.","summary":"Wing FTP Server does not verify that a user's base folder stays inside its allowed path. An attacker with admin rights can add user directories through scripts that escape the base folder, write arbitrary files, and reach remote code execution with the server's privileges, which can be root if the server was started with sudo.","severity":"critical","cvss":9.4,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["ftp","package","self-hosted","wing-ftp-server"],"not_affected_if":["no-admin-exposure","patched-8.2.6-or-later"],"how_to_check":"- Check the installed Wing FTP Server version against `8.2.6`\n- Review user home or base folder settings for paths outside the intended root\n- unknown","fix":"- Upgrade Wing FTP Server to `8.2.6` or later\n- Review admin accounts and rotate their credentials\n- Check for unexpected files created outside user base folders, especially root-owned ones","status":"open","published_at":"2026-10-28T14:16:56+00:00","first_seen_at":"2026-10-28T14:33:22+00:00","triaged_at":"2026-10-28T14:34:17+00:00","updated_at":"2026-10-28T14:34:17+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-28T14:34:17Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Wing FTP Server to `8.2.6` or later\n- Review admin accounts and rotate their credentials\n- Check for unexpected files created outside user base folders, especially root-owned ones","reach":"network","title":"Wing FTP Server: user base folder check lets admins write files outside it","impact":"high","summary":"Wing FTP Server does not verify that a user's base folder stays inside its allowed path. An attacker with admin rights can add user directories through scripts that escape the base folder, write arbitrary files, and reach remote code execution with the server's privileges, which can be root if the server was started with sudo.","category":"package","nicknames":[],"who_cares":["wing-ftp-server","self-hosted","ftp"],"confidence":0.7,"needs_auth":"yes","worst_case":"Code runs on the server, possibly as root","analyst_note":"Confirm the affected version range and whether the sudo install path makes files root-owned; check the NVD entry for version details.","how_to_check":"- Check the installed Wing FTP Server version against `8.2.6`\n- Review user home or base folder settings for paths outside the intended root\n- unknown","needs_analyst":true,"not_affected_if":["patched-8.2.6-or-later","no-admin-exposure"],"who_is_affected":"Sites running Wing FTP Server before `8.2.6`, especially installs started with sudo as the guide suggests, because files then land as root. Exposure requires admin access to the server, so the risk is highest where many people hold admin rights or admin credentials are weak. Teams not running Wing FTP Server can skip it.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"critical"},"cost_usd":0.000625,"input_tokens":3330,"output_tokens":584,"severity_before":"critical"},"analyst_status":null,"analyst_note":null,"search":"'-105420':15A,18A '-2026':14A,17A '8.2.6':158C 'add':51B,101C,108C 'admin':9A,48B,98C 'allow':43B,106C,116C 'arbitrari':62B 'attack':46B,96C,118C 'base':5A,38B,59B,93C,113C 'check':7A 'code':67B,130C 'command':143C 'creat':149C 'cve':13A,16A 'directori':53B,103C,109C 'escap':57B,111C 'execut':68B,131C 'file':11A,63B,121C,147C 'fix':155C 'folder':6A,39B,60B,94C,114C 'ftp':2A,19B,26B,29B,86C 'guid':139C 'host':23B 'insid':41B 'instal':138C 'issu':153C 'lead':127C 'let':8A 'mention':140C 'outsid':12A 'owner':134C 'packag':20B 'path':44B 'privileg':73B,99C 'privileges.critically':135C 'process':133C 'reach':65B 'remot':66B,129C 'right':49B 'root':77B,151C 'run':141C 'script':55B,105C 'self':22B 'self-host':21B 'server':3A,27B,30B,71B,80B,87C 'sinc':136C 'start':82B 'stay':40B 'sudo':84B,145C 'system':124C 'user':4A,36B,52B,91C,102C 'verifi':33B,90C 'version':157C 'via':104C 'wing':1A,25B,28B,85C 'wing-ftp-serv':24B 'write':10A,61B,120C","nicknames":[],"mitigations":[],"who_affected":"Sites running Wing FTP Server before `8.2.6`, especially installs started with sudo as the guide suggests, because files then land as root. Exposure requires admin access to the server, so the risk is highest where many people hold admin rights or admin credentials are weak. Teams not running Wing FTP Server can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-28T14:16:56+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"cvd@cert.pl","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-105420","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-105420","severity":null,"published_at":"2026-10-28T14:16:56+00:00","modified_at":"2026-10-28T14:16:56+00:00","first_seen_at":"2026-10-28T14:33:22+00:00","fetched_at":"2026-10-28T14:33:22+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}