diff --git a/BTCPayServer/Controllers/WalletsController.cs b/BTCPayServer/Controllers/WalletsController.cs
index 874479b1a..45bf13b30 100644
--- a/BTCPayServer/Controllers/WalletsController.cs
+++ b/BTCPayServer/Controllers/WalletsController.cs
@@ -90,6 +90,9 @@ namespace BTCPayServer.Controllers
             "#000000",
             "#cc317c",
         };
+
+        const int MaxLabelSize = 20;
+        const int MaxCommentSize = 200;
         [HttpPost]
         [Route("{walletId}")]
         public async Task<IActionResult> ModifyTransaction(
@@ -127,7 +130,7 @@ namespace BTCPayServer.Controllers
             var walletTransactionsInfo = await walletTransactionsInfoAsync;
             if (addlabel != null)
             {
-                addlabel = addlabel.Trim().ToLowerInvariant();
+                addlabel = addlabel.Trim().ToLowerInvariant().Truncate(MaxLabelSize);
                 var labels = walletBlobInfo.GetLabels();
                 if (!walletTransactionsInfo.TryGetValue(transactionId, out var walletTransactionInfo))
                 {
@@ -154,7 +157,7 @@ namespace BTCPayServer.Controllers
             }
             else if (removelabel != null)
             {
-                removelabel = removelabel.Trim().ToLowerInvariant();
+                removelabel = removelabel.Trim().ToLowerInvariant().Truncate(MaxLabelSize);
                 if (walletTransactionsInfo.TryGetValue(transactionId, out var walletTransactionInfo))
                 {
                     if (walletTransactionInfo.Labels.Remove(removelabel))
@@ -171,7 +174,7 @@ namespace BTCPayServer.Controllers
             }
             else if (addcomment != null)
             {
-                addcomment = addcomment.Trim();
+                addcomment = addcomment.Trim().Truncate(MaxCommentSize);
                 if (!walletTransactionsInfo.TryGetValue(transactionId, out var walletTransactionInfo))
                 {
                     walletTransactionInfo = new WalletTransactionInfo();
diff --git a/BTCPayServer/Extensions.cs b/BTCPayServer/Extensions.cs
index f008ea785..4dc0f2c55 100644
--- a/BTCPayServer/Extensions.cs
+++ b/BTCPayServer/Extensions.cs
@@ -40,6 +40,12 @@ namespace BTCPayServer
 {
     public static class Extensions
     {
+        public static string Truncate(this string value, int maxLength)
+        {
+            if (string.IsNullOrEmpty(value))
+                return value;
+            return value.Length <= maxLength ? value : value.Substring(0, maxLength);
+        }
         public static IServiceCollection AddStartupTask<T>(this IServiceCollection services)
             where T : class, IStartupTask
             => services.AddTransient<IStartupTask, T>();
diff --git a/BTCPayServer/Views/Wallets/WalletTransactions.cshtml b/BTCPayServer/Views/Wallets/WalletTransactions.cshtml
index b8f1b4da6..1cdaa6a66 100644
--- a/BTCPayServer/Views/Wallets/WalletTransactions.cshtml
+++ b/BTCPayServer/Views/Wallets/WalletTransactions.cshtml
@@ -87,7 +87,7 @@
                                     <form asp-action="ModifyTransaction" method="post">
                                         <input type="hidden" name="transactionId" value="@transaction.Id" />
                                         <div class="dropdown-item input-group">
-                                            <input name="addlabel" type="text" class="form-control form-control-sm" />
+                                            <input name="addlabel" maxlength="20" type="text" class="form-control form-control-sm" />
                                             <div class="input-group-append">
                                                 <button type="submit" class="btn btn-primary btn-sm"><span class="fa fa-plus"></span></button>
                                             </div>
@@ -119,7 +119,7 @@
                                 <div class="dropdown-menu">
                                     <form asp-action="ModifyTransaction" method="post">
                                         <input type="hidden" name="transactionId" value="@transaction.Id" />
-                                        <textarea name="addcomment" class="dropdown-item" rows="2" cols="20">@transaction.Comment</textarea>
+                                        <textarea name="addcomment" class="dropdown-item" maxlength="200" rows="2" cols="20">@transaction.Comment</textarea>
                                         <div class="dropdown-item"><button type="submit" class="btn btn-primary">Save comment</button></div>
                                     </form>
                                 </div>