diff --git a/Sources/CBORCoding/CBORParser.swift b/Sources/CBORCoding/CBORParser.swift
index c7f7c0d..52a20da 100644
--- a/Sources/CBORCoding/CBORParser.swift
+++ b/Sources/CBORCoding/CBORParser.swift
@@ -20,10 +20,10 @@ internal class CBORParser {
         guard !data.isEmpty else { return nil }
 
         var storage = Storage()
-        var index: Int = 0
+        var index: Int = data.startIndex
 
         do {
-            while index < data.count {
+            while index < data.endIndex {
                 let majorType = CBOR.majorType(for: data[index])
 
                 switch majorType {
diff --git a/Tests/CBORCodingTests/CBORParserTests.swift b/Tests/CBORCodingTests/CBORParserTests.swift
index 5043561..7ef8418 100644
--- a/Tests/CBORCodingTests/CBORParserTests.swift
+++ b/Tests/CBORCodingTests/CBORParserTests.swift
@@ -1075,6 +1075,18 @@ class CBORParserTests: XCTestCase {
 
         XCTAssertThrowsError(try CBORParser.testCreateCodingKey(from: UInt64.max))
     }
+    
+    func testSlicedDataInput() {
+        var value: Any!
+        
+        // Skip over the first 2 bytes with a slice.
+        let data = convertFromHexString("0x000000")[2...]
+        
+        XCTAssertNoThrow(value = try CBORParser.parse(data))
+        XCTAssertTrue(value is UInt64)
+        XCTAssertEqual(value as! UInt64, 0)
+
+    }
 
     // MARK: Private Methods