{"id":"CVE-2026-107810","aliases":["GHSA-p8v3-89rh-jxc7","GO-2026-6707"],"url":"https://o3.security/vulnerability/CVE-2026-107810","summary":"Nginx UI: Backup restore follows crafted symlinks into the live Nginx configuration path before restore flags are applied","details":"### Summary\nAn authenticated user who can create and restore a backup can craft a valid backup archive that causes the restore staging process to write attacker-controlled files into the live Nginx configuration path even when both `restore_nginx` and `restore_nginx_ui` are set to `false`.\n\n### Details\nThe restore flow always extracts the outer archive, verifies the manifest, decrypts `nginx-ui.zip` and `nginx.zip`, and extracts both inner archives before it decides whether `RestoreNginx` or `RestoreNginxUI` should be applied. The zip extractor explicitly allows absolute symlinks when the link target is under `nginx.GetConfPath()` or `nginx.GetModulesPath()`. Later regular-file entries are then created with `os.OpenFile()` on the symlinked path, which follows the symlink and writes into the live path.\n\nRelevant code paths:\n- [internal/backup/restore.go](/home/kali/Desktop/bounty/nginx-ui/internal/backup/restore.go:39)\n- [internal/backup/restore.go](/home/kali/Desktop/bounty/nginx-ui/internal/backup/restore.go:79)\n- [internal/backup/restore.go](/home/kali/Desktop/bounty/nginx-ui/internal/backup/restore.go:204)\n- [internal/backup/restore.go](/home/kali/Desktop/bounty/nginx-ui/internal/backup/restore.go:286)\n- [api/backup/restore.go](/home/kali/Desktop/bounty/nginx-ui/api/backup/restore.go:31)\n- [api/backup/backup.go](/home/kali/Desktop/bounty/nginx-ui/api/backup/backup.go:15)\n\nThis means the restore trust boundary is broken during extraction. A restore request that explicitly opted out of restoring either Nginx or Nginx UI can still modify the live Nginx configuration tree during staging.\n\n### PoC\nI verified this locally in an isolated environment with a temporary package-level harness that exercised the real `Backup()` and `Restore()` implementations.\n\nWhat the executed test did:\n1. Created a temporary `app.ini`, database file, and a temporary live Nginx config directory.\n2. Called the real `Backup()` implementation to obtain a valid backup archive plus AES key/IV.\n3. Extracted the outer backup, decrypted `nginx.zip`, replaced it with a crafted zip containing:\n   - a symlink entry `link -> <live nginx conf dir>`\n   - a later regular file entry `link/poc.conf`\n4. Recomputed `manifest.json` size/hash values for the modified encrypted `nginx.zip` and re-signed `manifest.sig` with the expected signing key derived from the AES key.\n5. Repacked the outer archive and called the real `Restore()` implementation with:\n   - `RestoreNginx: false`\n   - `RestoreNginxUI: false`\n6. Verified that `<live nginx conf dir>/poc.conf` was created anyway.\n\nObserved result from the actual local verification:\n- The crafted restore completed successfully with both restore flags set to `false`.\n- The asserted sink was the existence and content of the live-path file written during restore staging.\n\n### Impact\nAny deployment that allows an authenticated user to create and restore backups is affected. A crafted restore archive can modify the live Nginx configuration path before either restore toggle is honored. This can lead to persistent configuration injection, denial of service on a later reload, or other follow-on impact depending on what files the deployment later consumes from the modified path.","published":"2026-10-09T15:25:26.604Z","modified":"2026-10-21T02:54:37.595931412Z","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":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Go","name":"github.com/0xJacky/Nginx-UI","fixedVersion":"1.9.10-0.20260728074146-a467ed652591"}],"fix":{"url":"https://github.com/0xJacky/nginx-ui/commit/a467ed652591fc0cd1b466a1ec751b493faef9f7","label":"0xJacky/nginx-ui@a467ed6"},"references":[{"type":"WEB","url":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.5.0"},{"type":"ADVISORY","url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-p8v3-89rh-jxc7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107810.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107810"},{"type":"FIX","url":"https://github.com/0xJacky/nginx-ui/commit/a467ed652591fc0cd1b466a1ec751b493faef9f7"},{"type":"PACKAGE","url":"https://github.com/0xJacky/nginx-ui"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:54:37.595931412Z"}}