diff --git a/src/Avalonia.Base/Platform/Internal/SlicedStream.cs b/src/Avalonia.Base/Platform/Internal/SlicedStream.cs
index 124c248aa8..86a8dd5da9 100644
--- a/src/Avalonia.Base/Platform/Internal/SlicedStream.cs
+++ b/src/Avalonia.Base/Platform/Internal/SlicedStream.cs
@@ -29,7 +29,7 @@ internal class SlicedStream : Stream
         if (origin == SeekOrigin.Begin)
             Position = offset;
         if (origin == SeekOrigin.End)
-            Position = _from + Length + offset;
+            Position = Length + offset;
         if (origin == SeekOrigin.Current)
             Position = Position + offset;
         return Position;
diff --git a/tests/Avalonia.Base.UnitTests/Platform/SlicedStreamTests.cs b/tests/Avalonia.Base.UnitTests/Platform/SlicedStreamTests.cs
new file mode 100644
index 0000000000..dbcabf997c
--- /dev/null
+++ b/tests/Avalonia.Base.UnitTests/Platform/SlicedStreamTests.cs
@@ -0,0 +1,29 @@
+using System.IO;
+using Avalonia.Platform.Internal;
+using Xunit;
+
+namespace Avalonia.Base.UnitTests;
+
+public class SlicedStreamTests
+{
+    [Theory]
+    [InlineData(2, SeekOrigin.Begin, 22, 2, 9)]
+    [InlineData(2, SeekOrigin.Current, 22, 17, 24)]
+    [InlineData(-2, SeekOrigin.End, 22, 40, 47)]
+    public void Seek_Works(
+        long offset,
+        SeekOrigin origin,
+        long startingUnderlyingPosition,
+        long expectedPosition,
+        long expectedUnderlyingPosition)
+    {
+        var memoryStream = new MemoryStream(new byte[1024]);
+        var slicedStream = new SlicedStream(memoryStream, 7, 42);
+        memoryStream.Position = startingUnderlyingPosition;
+
+        slicedStream.Seek(offset, origin);
+
+        Assert.Equal(expectedPosition, slicedStream.Position);
+        Assert.Equal(expectedUnderlyingPosition, memoryStream.Position);
+    }
+}