diff --git a/samples/Dressca/dressca-backend/src/Dressca.ApplicationCore/ApplicationService/AssetApplicationService.cs b/samples/Dressca/dressca-backend/src/Dressca.ApplicationCore/ApplicationService/AssetApplicationService.cs
index 49a4eea6e..1d4ee27fc 100644
--- a/samples/Dressca/dressca-backend/src/Dressca.ApplicationCore/ApplicationService/AssetApplicationService.cs
+++ b/samples/Dressca/dressca-backend/src/Dressca.ApplicationCore/ApplicationService/AssetApplicationService.cs
@@ -46,7 +46,9 @@ public AssetApplicationService(
     /// </exception>
     public async Task<AssetStreamInfo> GetAssetStreamInfoAsync(string assetCode)
     {
-        this.logger.LogDebug(Events.DebugEvent, LogMessages.AssetApplicationService_GetAssetStreamInfoStart, assetCode);
+        // ログインジェクションを防ぐために改行文字を取り除きます。
+        var sanitizedAssetCode = assetCode.RemoveNewlineCharacters();
+        this.logger.LogDebug(Events.DebugEvent, LogMessages.AssetApplicationService_GetAssetStreamInfoStart, sanitizedAssetCode);
 
         Asset? asset;
         Stream? stream;
@@ -68,7 +70,7 @@ public async Task<AssetStreamInfo> GetAssetStreamInfoAsync(string assetCode)
             scope.Complete();
         }
 
-        this.logger.LogDebug(Events.DebugEvent, LogMessages.AssetApplicationService_GetAssetStreamInfoEnd, assetCode);
+        this.logger.LogDebug(Events.DebugEvent, LogMessages.AssetApplicationService_GetAssetStreamInfoEnd, sanitizedAssetCode);
         return new(asset, stream);
     }
 
diff --git a/samples/Dressca/dressca-backend/src/Dressca.EfInfrastructure/Migrations/20241211091203_InitialCreate.cs b/samples/Dressca/dressca-backend/src/Dressca.EfInfrastructure/Migrations/20241211091203_InitialCreate.cs
index b00b8bc67..627a745a5 100644
--- a/samples/Dressca/dressca-backend/src/Dressca.EfInfrastructure/Migrations/20241211091203_InitialCreate.cs
+++ b/samples/Dressca/dressca-backend/src/Dressca.EfInfrastructure/Migrations/20241211091203_InitialCreate.cs
@@ -1,5 +1,4 @@
-using System;
-using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
 
diff --git a/samples/Dressca/dressca-backend/src/Dressca.SystemCommon/StringExtentions.cs b/samples/Dressca/dressca-backend/src/Dressca.SystemCommon/StringExtentions.cs
new file mode 100644
index 000000000..e370dc05a
--- /dev/null
+++ b/samples/Dressca/dressca-backend/src/Dressca.SystemCommon/StringExtentions.cs
@@ -0,0 +1,25 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace System;
+
+/// <summary>
+///  <see cref="string"/> クラスの拡張メソッドを提供します。
+/// </summary>
+public static class StringExtentions
+{
+    /// <summary>
+    ///  対象の文字列から改行文字（\r、\n）を取り除きます。
+    /// </summary>
+    /// <param name="target">対象の文字列。</param>
+    /// <returns>元の文字列から改行文字を取り除いた文字列。</returns>
+    [return: NotNullIfNotNull(nameof(target))]
+    public static string? RemoveNewlineCharacters(this string? target)
+    {
+        if (target == null)
+        {
+            return null;
+        }
+
+        return target.Replace("\n", string.Empty).Replace("\r", string.Empty);
+    }
+}
diff --git a/samples/Dressca/dressca-backend/tests/Dressca.UnitTests.SystemCommon/StringExtentionsTest.cs b/samples/Dressca/dressca-backend/tests/Dressca.UnitTests.SystemCommon/StringExtentionsTest.cs
new file mode 100644
index 000000000..9e1ffcaec
--- /dev/null
+++ b/samples/Dressca/dressca-backend/tests/Dressca.UnitTests.SystemCommon/StringExtentionsTest.cs
@@ -0,0 +1,88 @@
+namespace Dressca.UnitTests.SystemCommon;
+
+public class StringExtentionsTest
+{
+    [Theory]
+    [InlineData("\r\nLine1Line2", "Line1Line2")] // CRとLFを含む、先頭
+    [InlineData("Line1\rLine2", "Line1Line2")] // CRのみを含む、中間
+    [InlineData("Line1Line2\n", "Line1Line2")] // LFのみを含む、末尾
+    public void RemoveNewlineCharacters_改行文字があれば取り除かれる(string input, string expected)
+    {
+        // Arrange
+
+        // Act
+        var actual = input.RemoveNewlineCharacters();
+
+        // Assert
+        Assert.Equal(expected, actual);
+    }
+
+    [Fact]
+    public void RemoveNewlineCharacters_改行文字なし_変化なし()
+    {
+        // Arrange
+        var target = "Line1Line2";
+
+        // Act
+        var actual = target.RemoveNewlineCharacters();
+
+        // Assert
+        Assert.Equal(target, actual);
+    }
+
+    [Fact]
+    public void RemoveNewlineCharacters_null_nullを返却()
+    {
+        // Arrange
+        string? target = null;
+
+        // Act
+        var actual = target.RemoveNewlineCharacters();
+
+        // Assert
+        Assert.Null(actual);
+    }
+
+    [Fact]
+    public void RemoveNewlineCharacters_空文字_変化なし()
+    {
+        // Arrange
+        var target = string.Empty;
+
+        // Act
+        var actual = target.RemoveNewlineCharacters();
+
+        // Assert
+        Assert.Equal(target, actual);
+    }
+
+    [Theory]
+    [InlineData(" ")]
+    [InlineData("　")]
+    public void RemoveNewlineCharacters_空白文字_変化なし(string target)
+    {
+        // Arrange
+
+        // Act
+        var actual = target.RemoveNewlineCharacters();
+
+        // Assert
+        Assert.Equal(target, actual);
+    }
+
+    [Theory]
+    [InlineData("\r\n")]
+    [InlineData("\r")]
+    [InlineData("\n")]
+    public void RemoveNewlineCharacters_改行コードのみ_取り除かれて空文字になる(string target)
+    {
+        // Arrange
+        var expected = string.Empty;
+
+        // Act
+        var actual = target.RemoveNewlineCharacters();
+
+        // Assert
+        Assert.Equal(expected, actual);
+    }
+}