GHSA-7jrr-xw9c-mj39: Nginx-UI: Authenticated settings disclosure exposes node.secret and enables trusted-node authentication abuse, backup exfiltration, and restore-based nginx-ui state rollback
SummaryAn authenticated user can call `GET /api/settings` and retrieve sensitive configuration values, including `node.secret`. The same `node.secret` is accepted by `AuthRequired()` through the `X-Node-Secret` header (or `node_secret` query parameter), causing the request to be treated as authenticated via the trusted-node path and associated with the init user.
In my local reproduction on `v2.3.6`, `GET /api/settings` also returned `app.jwt_secret`. After extracting `node.secret`, I was able to access `GET /api/backup` using only `X-Node-Secret`, download a full backup archive, and obtain the `X-Backup-Security` response header containing the backup decryption material (`AESKey:AESIv`).
I also confirmed that the disclosed `node.secret` is sufficient to reach the restore workflow on an installed instance. Using only `X-Node-Secret`, a valid backup archive, and its matching `X-Backup-Security` token, I successfully invoked `POST /api/restore`. In a follow-up rollback test, I changed `node.name` to `rollback-poc-B`, then restored a previously captured backup and observed the value revert to its original state. This extends the issue beyond secret disclosure and backup exfiltration into confirmed integrity impact through restore-based rollback of nginx-ui state/configuration.
This breaks the trust boundary between ordinary user-authenticated API access and the internal node-authentication mechanism, and results in sensitive configuration disclosure, alternate-authentication abuse, backup exfiltration with decryption material, and confirmed restore-based rollback of nginx-ui state.DetailsVulnerable code / related files and functions**1) Route exposure and insufficient protection on the read path**File: `api/settings/router.go`Relevant function: `InitRouter`The settings router exposes the following endpoints:The key issue is that the read path (GET /api/settings) is only protected by the generic authentication middleware, while the write path (POST /api/settings) has an additional RequireSecureSession() check. This makes the read path a much easier place to leak sensitive configuration data than the write path.**2) Sensitive data is disclosed by GetSettings**File: `api/settings/settings.go`Relevant functions: GetSettings, SaveSettings`GetSettings` returns multiple configuration objects directly in the JSON response, including app, server, database, auth, casdoor, oidc, cert, http, logrotate, nginx, node, openai, terminal, and webauthn. In other words, the handler does not use a redacted DTO for user-facing output; it serializes the live settings objects directly.In my local reproduction on v2.3.6, this response exposed both:This makes GetSettings the direct disclosure source for the vulnerability.**3) The disclosed value is explicitly defined as protected/sensitive**File: `settings/node.go`Relevant object: type NodeThe Node settings object defines the following field:The `protected:"true"` tag shows that the codebase itself treats `node.secret` as a protected/sensitive value. Despite that, the field is still returned unredacted by `GetSettings`. This strongly indicates a real secret disclosure issue rather than a harmless configuration read.**4) The disclosed secret is reused as an authentication credential**File: `internal/middleware/middleware.go`Relevant functions: getNodeSecret, AuthRequired, AuthRequiredWSThe authentication middleware contains a separate node-secret authentication path:`getNodeSecret(c)` reads the value from the `X-Node-Secret` header or the `node_secret` query parameter.AuthRequired() checks whether the supplied value equals settings.NodeSettings.Secret.If it matches, the middleware:
      loads initUser := user.GetInitUser(c)
      stores Secret in the context
      stores user in the contextallows the request to proceed without relying on the ordinary JWT path for that identity flowThis is the sink of the vulnerability: the same secret disclosed by GET /api/settings is accepted as a valid authentication credential by the middleware.AuthRequiredWS() contains similar logic for the WebSocket path, meaning the same secret is also trusted by the WebSocket authentication flow.**5) The write path already treats these fields as protected, but the read path does not**File: `api/settings/settings.go`Relevant function: SaveSettings`SaveSettings()` already uses ProtectedFill(...) for several settings objects, including:This shows the project already recognizes that these objects contain protected fields on the write path. However, GetSettings() still returns the raw objects on the read path, creating a clear “write-protected but read-exposed” inconsistency. That inconsistency is the core authorization/secret-handling flaw here.**6) Backup endpoint reachable after alternate authentication**File: `api/backup/router.go`, `api/backup/backup.go`Relevant functions: `InitRouter`, `CreateBackup`The backup route is exposed as:This route is protected by the same AuthRequired() middleware chain as other authenticated API routes.In `CreateBackup()`, the server returns the backup archive to the caller and also sets the X-Backup-Security response header containing the decryption material:As a result, once node.secret is disclosed from /api/settings and reused through X-Node-Secret, the attacker can access /api/backup and obtain both the encrypted backup and the decryption token in the same response.This means the disclosed secret is not only usable for low-risk authenticated reads, but also for high-impact data exfiltration through the backup subsystem.**7) Restore endpoint is reachable and usable after alternate authentication**File: `api/backup/router.go`, `api/backup/restore.go`, `internal/backup/restore.go`Relevant functions: `authIfInstalled`, `RestoreBackup`, internal restore helpersThe restore route is exposed as:On installed instances, authIfInstalled calls AuthRequired(). Because AuthRequired() accepts X-Node-Secret and associates the request with the init user, the same disclosed node.secret can be used to reach the restore workflow, not just read-only or backup routes.RestoreBackup() accepts:backup_filesecurity_tokenrestore_nginxrestore_nginx_uiverify_hashIt parses the security_token as AESKey:AESIv, decodes both values from base64, saves the uploaded backup archive to a temporary location, and then calls the internal restore logic.In my local reproduction on v2.3.6, a request to POST /api/restore using only:X-Node-Secreta valid backup archivethe matching X-Backup-Security tokenreturned:for a no-op restore test, confirming that the restore path was reachable and processed successfully via the trusted-node authentication path.I then performed an observable rollback test. After changing node.name to rollback-poc-B, I restored a previously captured backup using only X-Node-Secret plus the matching backup/security token pair. The server returned:and GET /api/settings/server/name changed from:back to its original empty value after the restore completed.This confirms that the disclosed node.secret is sufficient not only for backup exfiltration, but also for successful restore invocation and rollback of nginx-ui state/configuration.**Why these files together form the vulnerability**These files combine into a single exploitable chain:`api/settings/router.go` exposes the settings read endpoint to authenticated callers.`api/settings/settings.go:GetSettings` returns raw settings objects, disclosing node.secret and other sensitive values.`settings/node.go` confirms that node.secret is explicitly treated as a protected field.`internal/middleware/middleware.go:AuthRequired` accepts that same secret as a valid alternate authentication factor and associates the request with the init user.For that reason, this is not just a “settings disclosure” issue. It is more accurately described as:Vulnerable source-to-sink pathThe vulnerable chain spans the settings API, node authentication middleware, backup subsystem, and restore subsystem.**Source**An authenticated caller can reach:`GET /api/settings`The handler returns raw settings objects directly in the JSON response, including:`settings.NodeSettings``cSettings.AppSettings``settings.OpenAISettings`other configuration objectsIn my local reproduction on `v2.3.6`, the response exposed:`node.secret``app.jwt_secret`**Propagation**The attacker extracts `node.secret` from the `/api/settings` response and reuses it as:`X-Node-Secret` header`, or`node_secret` query parameter`**Authentication sink**`AuthRequired()` in `internal/middleware/middleware.go` checks whether the supplied node secret matches `settings.NodeSettings.Secret`. If it matches, the middleware loads `initUser := user.GetInitUser(c)`, stores the user in the request context, and allows the request to proceed without using the ordinary JWT path for that identity flow.**Post-authentication sinks**After satisfying `AuthRequired()` through `X-Node-Secret`, the attacker can reach additional protected routes, including:`GET /api/settings/server/name``GET /api/settings``GET /api/backup``POST /api/restore` (on installed instances via `authIfInstalled` → `AuthRequired()`)`In particular:`GET /api/backup` returns the backup archive and sets the `X-Backup-Security` response header containing the decryption material (`AESKey:AESIv`)``POST /api/restore` accepts a backup archive plus the matching `security_token` and executes the restore workflowThis creates the following end-to-end source-to-sink chain:Authenticated caller reaches `GET /api/settings`Response discloses `node.secret` (and in my lab also `app.jwt_secret`)Attacker reuses `node.secret` as `X-Node-Secret``AuthRequired()` accepts the request on the trusted-node path and associates it with the init userAttacker accesses `GET /api/backup`Server returns the encrypted backup archive and `X-Backup-Security` decryption material in the same responseAttacker submits the captured backup and matching token to `POST /api/restore` using only `X-Node-Secret`Server processes the restore request successfullynginx-ui state/configuration can be rolled back to the contents of the captured backupThis is not just a read-only disclosure chain. It is a disclosure-to-authentication-to-backup-to-restore chain with confirmed integrity impact.Why this is a vulnerability, not intended behaviorThis is not expected behavior for three reasons:`Node.Secret` is explicitly marked `protected:"true"`, indicating it is sensitive.`SaveSettings()` uses `ProtectedFill(...)` on NodeSettings, OpenAISettings, and other settings objects, showing the write path already treats these fields as protected/special.Despite that, GetSettings() still returns the raw secret-bearing objects to the caller, and the disclosed node.secret is immediately reusable as an authentication credential in middleware. That breaks the intended separation between user-facing configuration APIs and internal trusted-node authentication.Trust boundary that is brokenThe broken boundary is:A caller who is only supposed to use the normal JWT/cookie-based user path can retrieve a secret that belongs to the trusted-node path, then cross that boundary by presenting `X-Node-Secret` to `AuthRequired()`.Attacker model / required privilegesThe confirmed attacker requirement is:ability to authenticate to the web UI and call GET /api/settingsIn my local reproduction on v2.3.6, I reproduced this with a normal browser-authenticated session after resetting the initial account password in a fresh Docker deployment. The issue does not require shell access or direct database access. The route itself is protected, but the read-path has no additional redaction for secret-bearing settings, and the disclosed node secret can then be reused as alternate authentication.Additional confirmed impact: backup exfiltration through the trusted-node authentication pathThe impact is not limited to reading settings or downloading backups.In `api/backup/router.go`, the restore endpoint is exposed as:On installed instances, authIfInstalled calls AuthRequired(). Because AuthRequired() accepts X-Node-Secret and maps the request to the init user when the supplied secret matches settings.NodeSettings.Secret, the disclosed node.secret can also be reused to reach the restore workflow.In api/backup/restore.go, RestoreBackup() accepts:backup_filesecurity_tokenrestore_nginxrestore_nginx_uiverify_hashIt parses security_token as AESKey:AESIv, decodes both values from base64, saves the uploaded backup archive, and invokes the internal restore logic.In my local reproduction on v2.3.6, I first confirmed route reachability by submitting a valid backup archive and matching security_token using only X-Node-Secret, which returned:I then performed an observable rollback test:Captured a valid backup in state AChanged node.name to rollback-poc-BVerified GET /api/settings/server/name returned rollback-poc-BSubmitted the previously captured backup to POST /api/restore using only X-Node-Secret and the matching security_token
Received:Verified GET /api/settings/server/name returned the original empty value after restoreThis confirms that the disclosed node.secret is sufficient not only for backup exfiltration, but also for successful restore invocation and rollback of nginx-ui state/configuration through the trusted-node authentication path.PoCReproduction environmentProduct: 0xJacky/nginx-uiConfirmed version: v2.3.6Deployment method: local Docker lab on http://127.0.0.1:8080 using uozi/nginx-ui:latest at the time of testing.Exact reproduction steps1.Start a fresh local Docker deployment of uozi/nginx-ui:latest.Optional convenience settings I used in the lab:These are documented environment settings supported by Nginx UI.2.Reset the initial account password using the official command:The application prints the username/password for the initial account.
[Screenshot 1: password reset output showing the initial username/password]
<img width="1919" height="274" alt="image" src="https://github.com/user-attachments/assets/ec37a0f1-8de5-42dd-beee-c6ddac458ab8" />3.Log in through the browser and capture the JWT token from the login response or the token cookie.
[Screenshot 2: browser/devtools showing authenticated session and token]
<img width="1535" height="746" alt="image" src="https://github.com/user-attachments/assets/012b65a4-fa51-44a2-a8d0-bcb6a733cffa" />4.Send:In my reproduction, the response contained:`node.secret``app.jwt_secret`other settings objects such as openai, oidc, casdoor, nginx, etc.Example PowerShell:[Screenshot 3: /api/settings response showing node.secret and app.jwt_secret]
<img width="1706" height="978" alt="image" src="https://github.com/user-attachments/assets/25fc3c94-e5b3-4309-8b49-09633fbe3b89" />5.Verify that the protected route fails without authentication:Expected result: `403 Forbidden.`[Screenshot 4: unauthenticated 403]
<img width="1261" height="236" alt="image" src="https://github.com/user-attachments/assets/ba302b53-e4f7-414a-9a95-ea2b64a5e05a" />6.Re-send the same request with only `X-Node-Secret`:Expected result: 200 OK with a JSON body such as:{ "name": "" }[Screenshot 5: successful response using only X-Node-Secret]
<img width="1833" height="96" alt="image" src="https://github.com/user-attachments/assets/eef06152-2450-4701-9b06-6997d7ce24f5" />7.Re-send `GET /api/settings` using only `X-Node-Secret`:Expected result: 200 OK, and the response again includes node.secret.[Screenshot 6: /api/settings succeeding with only X-Node-Secret]
<img width="1708" height="835" alt="image" src="https://github.com/user-attachments/assets/7401ba0e-fb7e-4de8-970a-39f8077c0748" />8.Use the disclosed `node.secret` to access the backup endpoint:Expected result:HTTP status 200 OKa backup archive is written to diskthe response contains the X-Backup-Security header with backup decryption material in the format: `AESKey:AESIv`[Screenshot 7: successful /api/backup download using only X-Node-Secret]
<img width="1919" height="823" alt="image" src="https://github.com/user-attachments/assets/f76b8e5d-651b-47e0-a08c-7e2dfc6d4a00" />9.(Optional validation) Verify that the issue is not dependent on JWT forgery.I also tested whether the disclosed app.jwt_secret could be used to forge a valid JWT for standard authenticated routes. I generated a forged HS256 JWT using the leaked signing secret and attempted to access protected endpoints with the forged token.Example PowerShell:Observed result:forged JWT access to /api/settings/server/name returned 403forged JWT access to /api/settings returned 403forged JWT access to /api/backup returned 403This suggests the standard JWT path is additionally constrained by server-side token lookup and that the confirmed exploitation path is specifically the disclosed node.secret / X-Node-Secret alternate authentication route.[Screenshot : forged JWT requests returning 403]10.Confirm observable rollback of nginx-ui state using a previously captured backup.First, I captured a backup in state A:I then changed node.name through the normal authenticated settings write path to:and verified:Observed result:I then restored the previously captured state-A backup using only X-Node-Secret and the matching backup/security token:Observed result:After waiting a few seconds for the restore to apply, I queried the same setting again:Observed result:This confirmed successful rollback of nginx-ui state/configuration from rollback-poc-B back to the original value using only the disclosed node.secret, a valid backup archive, and the matching X-Backup-Security token.[Screenshot: node.name / server name before restore showing rollback-poc-B]
<img width="1517" height="175" alt="image" src="https://github.com/user-attachments/assets/e358a217-3089-45a1-9e66-87f78958a347" />[Screenshot: successful restore response showing nginx_ui_restored:true]
<img width="1671" height="423" alt="image" src="https://github.com/user-attachments/assets/5051b4c1-0ad7-4186-8158-fb7da593efef" />[Screenshot: same setting after restore showing rollback to the original value]
<img width="1707" height="319" alt="image" src="https://github.com/user-attachments/assets/eb9b5707-d90a-430e-92f9-6619ddf7f9cd" />Confirmed observed resultsIn my local reproduction on `v2.3.6`:`GET /api/settings` with a normal authenticated session returned:`node.secret = NodeSecret-Lab-123456``app.jwt_secret = JwtSecret-Lab-123456``GET /api/settings/server/name` without authentication returned `403``GET /api/settings/server/name` with only `X-Node-Secret: NodeSecret-Lab-123456` returned `200``GET /api/settings` with only `X-Node-Secret` returned `200``GET /api/backup` with only `X-Node-Secret` returned `200``/api/backup` returned both:a backup archivethe `X-Backup-Security` response header containing backup decryption material`POST /api/restore` without authentication failed with:POST /api/restore with only X-Node-Secret, a valid backup archive, and the matching X-Backup-Security token returned:after changing node.name to rollback-poc-B, GET /api/settings/server/name returned:restoring a previously captured backup using only X-Node-Secret and the matching X-Backup-Security token returned:after restore, GET /api/settings/server/name returned the original empty value, confirming rollback of nginx-ui state/configuration
forged JWT requests signed with the leaked app.jwt_secret failed with 403 on the tested standard protected routesImpactThe confirmed impact is:**Sensitive settings disclosure**  
An authenticated caller can retrieve sensitive configuration values through `GET /api/settings`, including:`node.secret``app.jwt_secret`other secret-bearing settings objects depending on deployment and enabled integrations**Alternate-authentication abuse**  
The disclosed `node.secret` can be reused through `X-Node-Secret` (or `node_secret`) to satisfy `AuthRequired()` and enter the trusted-node / init-user authentication path.**Trust-boundary bypass**  
An ordinary authenticated user can cross from the normal JWT/cookie-based user path into the internal node-authentication path.**Full backup exfiltration**  
After crossing that boundary, the attacker can access `GET /api/backup` and download the application's backup archive.**Backup decryption material disclosure**  
The same `/api/backup` response also includes the `X-Backup-Security` header containing the decryption material (`AESKey:AESIv`), allowing the attacker to decrypt the exported backup contents.**Restore workflow invocation through the trusted-node path**  
The disclosed `node.secret` is sufficient to reach `POST /api/restore` on an installed instance when combined with a valid backup archive and matching `X-Backup-Security` token.**Confirmed rollback of nginx-ui state/configuration**  
In my lab, I changed `node.name` to `rollback-poc-B`, then restored a previously captured backup using only `X-Node-Secret` and the matching backup/security token pair. After restore, the value reverted to its original state. This confirms real integrity impact through rollback of nginx-ui state/configuration.**Potential service disruption / operational impact**  
Because restore operations can trigger nginx-ui and/or nginx restart behavior depending on the selected restore options, abuse of the restore workflow may also create operational disruption in addition to confidentiality and integrity impact.**Potential downstream compromise**  
Depending on deployment and configured integrations, the exposed settings and exported backups may contain additional sensitive information such as:JWT signing secretsnode secretsthird-party API credentialsOIDC / Casdoor / OpenAI configurationoperational configuration data and other stored secretsNotes on JWT forgery testingI also tested whether the disclosed `app.jwt_secret` could be used for successful forged JWT access on standard authenticated routes. In my reproduction, forged HS256 JWTs signed with the leaked secret were rejected with `403` on `/api/settings/server/name`, `/api/settings`, and `/api/backup`.This indicates that the **confirmed exploitation path** is the disclosed `node.secret` and the `X-Node-Secret` trusted-node authentication route, not direct JWT forgery on standard routes.This matters because the confirmed impact already includes:backup exfiltrationdisclosure of backup decryption materialsuccessful restore invocationrollback of nginx-ui state/configurationwithout needing forged JWTs.Recommended fix**Do not return secret-bearing settings fields from `GET /api/settings`.**  
Replace the current raw response with a redacted DTO. At minimum, do not expose:`node.secret``app.jwt_secret`provider / API / client secretsany other secret-bearing settings fields**Require stronger authorization for settings read operations.**  
If `/api/settings` is intended only for trusted administrators or internal operators, enforce that explicitly instead of relying only on the generic authenticated middleware.**Do not use a secret retrievable from a user-facing API as an authentication credential.**  
The node secret should be scoped strictly to node-to-node communication and must never be readable through ordinary user-facing settings APIs.**Reassess use of `X-Node-Secret` as a full alternate-authentication mechanism.**  
If this mechanism must exist, it should be isolated from user-facing routes and should not map directly to privileged request context without additional scoping or separation.**Protect backup functionality against alternate-authentication abuse.**  
`/api/backup` should not be reachable through a secret that can be disclosed via `/api/settings`.**Protect restore functionality against trusted-node secret abuse.**  
On installed instances, `/api/restore` should not be invocable through a node secret disclosed from a user-facing API. Restore should require a stronger admin-only authorization model and should not be reachable through the same alternate-authentication path used for node trust.**Do not return backup decryption material in the same response as the backup file.**  
The current `X-Backup-Security` header exposes decryption material together with the encrypted archive, which defeats the security goal of backup encryption when the endpoint is reached by an unauthorized actor.**Consider requiring explicit re-authentication / secure-session semantics for restore.**  
Restore is a high-impact state-changing action and should be protected at least as strongly as other sensitive write operations.**Rotate compromised secrets on upgrade/fix.**  
After patching, rotate:node secretJWT signing secretbackup encryption materialany third-party credentials or secrets exposed through `/api/settings` or backup exports**Audit all settings objects returned by `GetSettings()` for secret leakage.**  
The current response includes multiple settings objects (`app`, `node`, `openai`, `oidc`, `casdoor`, etc.), so the remediation should be systematic rather than field-by-field only.A patch is available at https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8.
CVSS v3.1: 6.5