{"id":"CVE-2026-54593","aliases":["GHSA-8r6w-3qq5-4p4r","GO-2026-6120"],"url":"https://o3.security/vulnerability/CVE-2026-54593","summary":"Pterodactyl's improper JWT scoping allows subuser to upload files when not explicitly granted `file.create` permissions","details":"### Summary\nA privilege escalation vulnerability exists in the Wings /upload/file endpoint due to insufficient validation of panel-signed JWTs. Wings accepts any valid panel-signed JWT containing `server_uuid`, `user_uuid`, and `unique_id`, regardless of the token’s intended purpose. Because the Panel issues JWTs with these same claims for other lower-privilege operations (such as WebSocket authentication and file download links), an authenticated subuser can reuse one of those tokens to upload arbitrary files without possessing the required `file.create` permission.\n\n### Impact\nAny subuser with permission to connect to a server's console, download files, or download backups could reuse those tokens to upload arbitrary files to the _same server_. A user that does not have access to a server as a subuser is not able to arbitrarily upload files.\n\n### Details\nThe panel generated JWT tokens for various purposes:\n- https://github.com/pterodactyl/panel/blob/0f82c105201b192d229f6abd5827e2ee7e672a05/app/Services/Backups/DownloadLinkService.php#L33-L36\n- https://github.com/pterodactyl/panel/blob/0f82c105201b192d229f6abd5827e2ee7e672a05/app/Http/Controllers/Api/Client/Servers/FileUploadController.php#L45\n- https://github.com/pterodactyl/panel/blob/0f82c105201b192d229f6abd5827e2ee7e672a05/app/Http/Controllers/Api/Client/Servers/WebsocketController.php#L58-L61\n- https://github.com/pterodactyl/panel/blob/0f82c105201b192d229f6abd5827e2ee7e672a05/app/Http/Controllers/Api/Client/Servers/FileController.php#L82-L85\nThough as the actual purpose is not conveyed part of the JWT tokens, this introduces this vulnerability of being able to do non-intended actions due to the expected fields (i.e. `server_uuid`) on most endpoints being the same when parsing it on wings' side.  \n\n### PoC\nCreate a new subuser that has the minimal amount of permissions on a server (`websocket.connect`). As that subuser, retrieve a websocket JWT token from the `GET /api/client/servers/[...]/websocket` endpoint (in my case, I manually just make a request under that user's browser session; you can probably just resend the /websocket request in browser console to get a fresh unused token). Using that websocket token, we can abuse this by directly using it in the `/upload/file` endpoint of the wings node instead of using it for websocket authentication:\n```python3\nimport requests\n\nwings_url = 'http://[...]:8080'\nwebsocket_token = '[...]'\n\nres = requests.post(f'{wings_url}/upload/file', params = {\n    'token': websocket_token,\n}, files = {\n    'files': ('file-upload.txt', b'Hello, World!'),\n})\nprint(res.status_code, res.content)\n```\nObserve, that even though our subuser never has permissions outside viewing the console, they are able to write arbitrary files in the server. This pattern happens in a lot of other action, but this is probably the most interesting one.","published":"2026-07-28T15:42:56.971Z","modified":"2026-10-28T02:30:31.483462979Z","cvss":{"score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H"},"epss":{"score":0.00357,"percentile":0.2935,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/pterodactyl/wings","fixedVersion":"1.12.2"},{"ecosystem":"Packagist","name":"pterodactyl/panel","fixedVersion":"1.12.3"}],"fix":{"url":"https://github.com/pterodactyl/panel/commit/7ffcd636310bb72b54bac3280d2a15e727feded7","label":"pterodactyl/panel@7ffcd63"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54593.json"},{"type":"ADVISORY","url":"https://github.com/pterodactyl/panel/security/advisories/GHSA-8r6w-3qq5-4p4r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54593"},{"type":"FIX","url":"https://github.com/pterodactyl/panel/commit/7ffcd636310bb72b54bac3280d2a15e727feded7"},{"type":"FIX","url":"https://github.com/pterodactyl/panel/pull/5636"},{"type":"FIX","url":"https://github.com/pterodactyl/wings/commit/d0ddc80844479302abdaf9654de3bacd511c0f5c"},{"type":"PACKAGE","url":"https://github.com/pterodactyl/panel"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:31.483462979Z"}}