diff --git a/tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.cs b/tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.cs
index 9d04cf354..d78277528 100644
--- a/tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Jpg/JpegDecoderTests.cs
@@ -43,6 +43,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
                 TestImages.Jpeg.Baseline.Bad.BadEOF,
                 TestImages.Jpeg.Baseline.Bad.ExifUndefType,
                 TestImages.Jpeg.Issues.MultiHuffmanBaseline394,
+                TestImages.Jpeg.Issues.CmykIssueBaseline464
             };
 
         public static string[] ProgressiveTestJpegs =
diff --git a/tests/ImageSharp.Tests/Formats/Jpg/SpectralJpegTests.cs b/tests/ImageSharp.Tests/Formats/Jpg/SpectralJpegTests.cs
index 4508c6863..32c3be47d 100644
--- a/tests/ImageSharp.Tests/Formats/Jpg/SpectralJpegTests.cs
+++ b/tests/ImageSharp.Tests/Formats/Jpg/SpectralJpegTests.cs
@@ -29,6 +29,7 @@ namespace SixLabors.ImageSharp.Tests.Formats.Jpg
                 TestImages.Jpeg.Baseline.Jpeg444, TestImages.Jpeg.Baseline.Testorig420,
                 TestImages.Jpeg.Baseline.Jpeg420Small, TestImages.Jpeg.Baseline.Bad.BadEOF,
                 TestImages.Jpeg.Baseline.Bad.ExifUndefType,
+                TestImages.Jpeg.Issues.CmykIssueBaseline464
             };
 
         public static readonly string[] ProgressiveTestJpegs = 
diff --git a/tests/ImageSharp.Tests/TestImages.cs b/tests/ImageSharp.Tests/TestImages.cs
index 864c96332..bb66414fb 100644
--- a/tests/ImageSharp.Tests/TestImages.cs
+++ b/tests/ImageSharp.Tests/TestImages.cs
@@ -129,6 +129,7 @@ namespace SixLabors.ImageSharp.Tests
                 public const string BadCoeffsProgressive178 = "Jpg/issues/Issue178-BadCoeffsProgressive-Lemon.jpg";
                 public const string BadZigZagProgressive385 = "Jpg/issues/Issue385-BadZigZag-Progressive.jpg";
                 public const string MultiHuffmanBaseline394 = "Jpg/issues/Issue394-MultiHuffmanBaseline-Speakers.jpg";
+                public const string CmykIssueBaseline464 = "Jpg/issues/Issue464-CMYK-DecodedAsGrayscale.jpg";
             }
 
             public static readonly string[] All = Baseline.All.Concat(Progressive.All).ToArray();
diff --git a/tests/Images/External b/tests/Images/External
index 20f83891c..cdc178daa 160000
--- a/tests/Images/External
+++ b/tests/Images/External
@@ -1 +1 @@
-Subproject commit 20f83891ce75597486f5532010a8c5dea1419a4d
+Subproject commit cdc178daa552856157d1834ad136f9a28996a0f9
diff --git a/tests/Images/Input/Jpg/issues/Issue464-CMYK-DecodedAsGrayscale.jpg b/tests/Images/Input/Jpg/issues/Issue464-CMYK-DecodedAsGrayscale.jpg
new file mode 100644
index 000000000..0803f9e5d
Binary files /dev/null and b/tests/Images/Input/Jpg/issues/Issue464-CMYK-DecodedAsGrayscale.jpg differ