# GHSA-mpmw-f6h6-3g26: Winter: My Account preview exposes another backend user's profile by record ID

> Authenticated backend users can view other users' profile details by manipulating record IDs in the URL due to missing authorization checks.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Aug 2026

## What is GHSA-mpmw-f6h6-3g26?

GHSA-mpmw-f6h6-3g26 is a missing authorization vulnerability in winter/wn-backend-module, published on 20 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

### Impact

`Backend\Controllers\MyAccount`, introduced in v1.2.13, declares an empty `$requiredPermissions` array so that any authenticated backend user can manage their own account. It implements the `FormController` behavior, which exposes three routable actions — `create`, `update` and `preview` — that each take a record id from the URL.

`index()` passes the authenticated user's own id to the behavior, but the inherited actions were left routable and `formFindModelObject()` was not scoped, so a caller-supplied id resolved against an unscoped `Backend\Models\User` query:

```
GET /backend/backend/myaccount/preview/{other_user_id}
```

`preview` disclosed the target user's first name, last name, login, email address and avatar; `update` was equally routable and additionally disclosed role, group membership, superuser flag and throttle state. Password controls render a mask, so no credential material was exposed. Backend user ids are sequential and trivially enumerated, and as these are `GET` actions no CSRF token is involved.

The behavior's AJAX handlers (`create_onSave`, `update_onSave`, `update_onDelete`) were also dispatchable on these routes, but cross-user writes were blocked by the `Backend\Models\User` authorization guards added in v1.2.13. The confirmed impact is unauthorized disclosure of backend user profile data.

To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access.

### Patches

`MyAccount` no longer exposes the generic record actions it never used as routes, and its form lookup is now pinned to the authenticated user:

- `protected $guarded = ['create', 'update', 'preview'];` removes the inherited actions from routing. The guard has to be at the routing layer, as handler dispatch (`{action}_{handler}`) runs before the page action.
- `formExtendQuery()` constrains every lookup made by the behavior to the current user's key.

This security issue has been fixed as of **v1.2.14** (commit [`cdbc8f5a23db27f72ccec658a8e5769e6d9f6dcb`](https://github.com/wintercms/winter/commit/cdbc8f5a23db27f72ccec658a8e5769e6d9f6dcb)).

### Workarounds

There is no supported workaround other than upgrading. If you cannot upgrade immediately, you may apply the fix manually in `modules/backend/controllers/MyAccount.php`:

1. Add `protected $guarded = ['create', 'update', 'preview'];` to the controller.
2. Add a `formExtendQuery()` method that scopes the lookup to the current user:

```php
public function formExtendQuery(\Winter\Storm\Database\Builder $query): void
{
    $query->whereKey($this->user->getKey());
}
```

### References

- https://github.com/wintercms/winter/security/advisories/GHSA-j5jq-cr68-v2xx
- https://github.com/wintercms/winter/commit/cdbc8f5a23db27f72ccec658a8e5769e6d9f6dcb

Credit to Awwader ([@NRAwwad](https://github.com/NRAwwad)) for reporting the issue.

### For more information

If you have any questions or comments about this advisory:
- Email us at [hello@wintercms.com](mailto:hello@wintercms.com)

## Which versions are affected by GHSA-mpmw-f6h6-3g26?

2 open source packages ship an affected version, including winter/wn-backend-module.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `winter/wn-backend-module` | Packagist | From 1.2.13 | 1.2.14 |
| `winter/wn-backend-module` | Packagist | From 1.2.13 | 1.2.14 |

## How do I fix GHSA-mpmw-f6h6-3g26?

Upgrade winter/wn-backend-module to 1.2.14 or later.

## Is GHSA-mpmw-f6h6-3g26 being exploited?

There is no known exploitation of GHSA-mpmw-f6h6-3g26 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-mpmw-f6h6-3g26 and fix it if it is affected.

What it is: GHSA-mpmw-f6h6-3g26 is a missing authorization vulnerability in winter/wn-backend-module, published on 20 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-mpmw-f6h6-3g26 in the wild and no public exploit code.

Affected packages and fixed versions:
- winter/wn-backend-module (Packagist): affected from 1.2.13; fixed in 1.2.14
- winter/wn-backend-module (Packagist): affected from 1.2.13; fixed in 1.2.14

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GHSA-mpmw-f6h6-3g26/ (Markdown: https://insights.sbomify.com/GHSA-mpmw-f6h6-3g26/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-mpmw-f6h6-3g26

---
From sbomify Insights: https://insights.sbomify.com/GHSA-mpmw-f6h6-3g26/
Summaries are generated and may contain mistakes; the official description above is the record.