Cloudreve CVE-2026-55496

Summary

GET /api/v4/user/search is available to any logged-in user. The service calls userClient.SearchActive, but despite its name that method filters only by email/nickname keyword and never adds a StatusActive predicate - while the sibling lookups GetActiveByID and GetActiveByDavAccount, defined a few lines above it, do. Search hits are serialized at RedactLevelUser, which includes the email address.

A normal logged-in user can therefore enumerate and retrieve the email (plus nickname, avatar, creation time, redacted group, profile share-visibility) of inactive and banned accounts that an active-user directory is supposed to suppress. No global status interceptor compensates - the only User query interceptor is soft-delete, and inactive/banned rows are not soft-deleted.

Details

Root cause (verified at 26b6b10)

1. Route - logged-in + UserInfo.Read scope (routers/router.go):

user := v4.Group("user")            // protected user group (login required)
user.GET("search",
    middleware.RequiredScopes(types.ScopeUserInfoRead),
    controllers.FromQuery[usersvc.SearchUserService](...), controllers.UserSearch)

The RequiredScopes check applies to scoped OAuth tokens; plain session requests are not gated by it - so any logged-in user reaches the search.

2. Service - 2-char keyword to SearchActive (service/user/info.go):

type SearchUserService struct { Keyword string `form:"keyword" binding:"required,min=2"` }
const resultLimit = 10
func (s *SearchUserService) Search(c *gin.Context) ([]*ent.User, error) {
    return dep.UserClient().SearchActive(c, resultLimit, s.Keyword)
}

3. The bug - SearchActive has no status predicate (inventory/user.go):

func (c *userClient) SearchActive(ctx context.Context, limit int, keyword string) ([]*ent.User, error) {
    ctx = context.WithValue(ctx, LoadUserGroup{}, true)
    return withUserEagerLoading(ctx,
        c.client.User.Query().
            Where(user.Or(user.EmailContainsFold(keyword), user.NickContainsFold(keyword))).
            Limit(limit),                       // <-- no user.StatusEQ(user.StatusActive)
    ).All(ctx)
}

Contrast the siblings immediately above:

func (c *userClient) GetActiveByID(...)        { ... Where(user.ID(id)).Where(user.StatusEQ(user.StatusActive)) ... }
func (c *userClient) GetActiveByDavAccount(...) { ... Where(user.EmailEqualFold(email)).Where(user.StatusEQ(user.StatusActive)) ... }

withUserEagerLoading only eager-loads the group/passkey edges; it adds no status filter. Status values are active/inactive/manual_banned/sys_banned (ent/user/user.go).

4. No global status interceptor - User.Mixin() is CommonMixin{} (ent/schema/user.go), whose Interceptors() returns only softDeleteInterceptors (ent/schema/common.go). Inactive/banned users are not soft-deleted, so nothing filters them out at query time.

5. Results serialized with email (routers/controllers/user.go → service/user/response.go):

// UserSearch:
return user.BuildUserRedacted(item, user.RedactLevelUser, hasher)
// BuildUserRedacted:
if level == RedactLevelUser { user.Email = userRaw.Email }   // email included

Secondary path: GET /api/v4/user/info/:id → GetUser uses GetByID (no status filter), and the controller picks RedactLevelUser for any non-anonymous caller (RedactLevelAnonymous only for anonymous). So a logged-in caller with an inactive/banned user's hashed ID also receives the email-bearing profile. (Less practical than search, since it needs the hashed ID rather than a 2-char keyword.)

Steps to reproduce (requires a live instance)

1. Ensure a target account exists in inactive or manual_banned/sys_banned status (e.g., an unconfirmed registration or a banned user).
2. As any logged-in user:

   GET /api/v4/user/search?keyword=<>=2 chars of the target email/nick>
   Cookie: cloudreve-session=<attacker-session>

1. Observe the inactive/banned account in the results, including its email.

Expected: only active accounts appear (matching the method name and the sibling GetActive* behavior). Actual: inactive/banned accounts are returned with their email addresses.

Impact

Any logged-in user can enumerate and harvest the email addresses (and basic profile metadata) of inactive and banned accounts that active-user lookups intentionally hide. No account access, passwords, or 2FA secrets are exposed; the impact is PII leakage and user enumeration.

Remediation

• Add Where(user.StatusEQ(user.StatusActive)) to SearchActive (matching GetActiveByID).
• Apply the same active-status requirement to GET /api/v4/user/info/:id, or fall back to anonymous-level redaction unless the target account is active.
• Consider not returning email from directory search at all - display name + hashed ID is usually sufficient.
• Regression tests: searching a keyword that matches an inactive/banned account must return no result (or no email).