diff --git a/src/i18n/locales/en.json b/src/i18n/locales/en.json
index 6a863f7d..a8f3da02 100644
--- a/src/i18n/locales/en.json
+++ b/src/i18n/locales/en.json
@@ -204,7 +204,9 @@
       "validBoolean": "{0} must be a valid boolean",
       "validArray": "{0} must be a valid array",
       "stringMin": "{0} must be at least {1} Character",
-      "numberMin": "{0} must be at least {1}"
+      "stringMax": "{0} must be at most {1} Character",
+      "numberMin": "{0} must be at least {1}",
+      "numberMax": "{0} must be at most {1}"
     },
     "client": {
       "id": "Client ID",
diff --git a/src/server/api/auth/verify-2fa.post.ts b/src/server/api/auth/verify-2fa.post.ts
index 2fa19d86..51bbc718 100644
--- a/src/server/api/auth/verify-2fa.post.ts
+++ b/src/server/api/auth/verify-2fa.post.ts
@@ -1,8 +1,4 @@
-import { z } from 'zod';
-
-const Verify2faSchema = z.object({
-  totpCode: z.string().min(6).max(6),
-});
+import { Verify2faSchema } from '#db/repositories/user/types';
 
 export default defineEventHandler(async (event) => {
   const { totpCode } = await readValidatedBody(
diff --git a/src/server/database/repositories/client/types.ts b/src/server/database/repositories/client/types.ts
index b0aa7fa3..cffd694d 100644
--- a/src/server/database/repositories/client/types.ts
+++ b/src/server/database/repositories/client/types.ts
@@ -1,6 +1,7 @@
 import type { InferSelectModel } from 'drizzle-orm';
 import z from 'zod';
 
+import { isIPv4, isIPv6 } from 'is-ip';
 import type { client } from './schema';
 
 export type ClientType = InferSelectModel<typeof client>;
@@ -20,7 +21,8 @@ export type UpdateClientType = Omit<
 const name = z
   .string({ message: t('zod.client.name') })
   .min(1, t('zod.client.name'))
-  .pipe(safeStringRefine);
+  .pipe(safeStringRefine)
+  .pipe(controlStringRefine);
 
 // TODO?: validate iso string
 const expiresAt = z
@@ -32,14 +34,18 @@ const expiresAt = z
 const address4 = z
   .string({ message: t('zod.client.address4') })
   .min(1, { message: t('zod.client.address4') })
-  .pipe(safeStringRefine);
+  .pipe(safeStringRefine)
+  .pipe(controlStringRefine)
+  .refine((v) => isIPv4(v));
 
 const address6 = z
   .string({ message: t('zod.client.address6') })
   .min(1, { message: t('zod.client.address6') })
-  .pipe(safeStringRefine);
+  .pipe(safeStringRefine)
+  .pipe(controlStringRefine)
+  .refine((v) => isIPv6(v));
 
-const filter = z.string().optional();
+const filter = z.string().pipe(safeStringRefine).optional();
 
 const serverAllowedIps = z.array(AddressSchema, {
   message: t('zod.client.serverAllowedIps'),
diff --git a/src/server/database/repositories/general/types.ts b/src/server/database/repositories/general/types.ts
index e16bc4c6..3097f645 100644
--- a/src/server/database/repositories/general/types.ts
+++ b/src/server/database/repositories/general/types.ts
@@ -11,6 +11,7 @@ const metricsEnabled = z.boolean({ message: t('zod.general.metricsEnabled') });
 const metricsPassword = z
   .string({ message: t('zod.general.metricsPassword') })
   .min(1, { message: t('zod.general.metricsPassword') })
+  .pipe(safeStringRefine)
   .nullable();
 
 export const GeneralUpdateSchema = z.object({
diff --git a/src/server/database/repositories/user/types.ts b/src/server/database/repositories/user/types.ts
index 9a175a6a..043d560b 100644
--- a/src/server/database/repositories/user/types.ts
+++ b/src/server/database/repositories/user/types.ts
@@ -46,9 +46,8 @@ const name = z
   .pipe(safeStringRefine);
 
 const email = z
-  .string({ message: t('zod.user.email') })
-  .min(5, t('zod.user.email'))
   .email({ message: t('zod.user.emailInvalid') })
+  .min(5, t('zod.user.email'))
   .pipe(safeStringRefine)
   .nullable();
 
@@ -80,3 +79,7 @@ export const UserUpdateTotpSchema = z.union([
     currentPassword: password,
   }),
 ]);
+
+export const Verify2faSchema = z.object({
+  totpCode: totpCode,
+});
diff --git a/src/server/utils/types.ts b/src/server/utils/types.ts
index 526b69b9..b18bf2f0 100644
--- a/src/server/utils/types.ts
+++ b/src/server/utils/types.ts
@@ -1,4 +1,4 @@
-import type { ZodSchema } from 'zod';
+import type { ZodType } from 'zod';
 import z from 'zod';
 import type { H3Event, EventHandlerRequest } from 'h3';
 import { isIP } from 'is-ip';
@@ -20,6 +20,15 @@ export const safeStringRefine = z
     { message: t('zod.stringMalformed') }
   );
 
+function hasControlChars(str: string) {
+  // eslint-disable-next-line no-control-regex
+  return /[\x00-\x1F\x7F]/.test(str);
+}
+
+export const controlStringRefine = z
+  .string()
+  .refine((v) => !hasControlChars(v), { message: t('zod.stringMalformed') });
+
 export const EnabledSchema = z.boolean({ message: t('zod.enabled') });
 
 export const MtuSchema = z
@@ -70,7 +79,11 @@ export const HSchema = z
   })
   .nullable();
 
-export const ISchema = z.string().nullable();
+export const ISchema = z
+  .string()
+  .pipe(safeStringRefine)
+  .pipe(controlStringRefine)
+  .nullable();
 
 export const PortSchema = z
   .number({ message: t('zod.port') })
@@ -85,7 +98,8 @@ export const PersistentKeepaliveSchema = z
 export const AddressSchema = z
   .string({ message: t('zod.address') })
   .min(1, { message: t('zod.address') })
-  .pipe(safeStringRefine);
+  .pipe(safeStringRefine)
+  .pipe(controlStringRefine);
 
 export const DnsSchema = z.array(AddressSchema, { message: t('zod.dns') });
 
@@ -168,7 +182,7 @@ export const schemaForType =
   };
 
 export function validateZod<T>(
-  schema: ZodSchema<T>,
+  schema: ZodType<T>,
   event: H3Event<EventHandlerRequest>
 ) {
   return async (data: unknown) => {
@@ -203,6 +217,22 @@ export function validateZod<T>(
                         break;
                     }
                     break;
+                  case 'too_big':
+                    switch (v.origin) {
+                      case 'string':
+                        newMessage = t('zod.generic.stringMax', [
+                          t(v.message),
+                          v.maximum,
+                        ]);
+                        break;
+                      case 'number':
+                        newMessage = t('zod.generic.numberMax', [
+                          t(v.message),
+                          v.maximum,
+                        ]);
+                        break;
+                    }
+                    break;
                   case 'invalid_type': {
                     if (v.input === null || v.input === undefined) {
                       newMessage = t('zod.generic.required', [