Fix issue 458: Add null checking

cbor/src/main/java/com/fasterxml/jackson/dataformat/cbor/CBORParser.java

@@ -2224,6 +2224,9 @@ protected void convertNumberToBigDecimal() throws IOException
             // Let's parse from String representation, to avoid rounding errors that
             //non-decimal floating operations would incur
             final String text = getText();
+            if (text == null) {
+                throw _constructReadException("No more values");
+            }
             streamReadConstraints().validateFPLength(text.length());
             _numberBigDecimal = NumberInput.parseBigDecimal(
                     text, isEnabled(StreamReadFeature.USE_FAST_BIG_NUMBER_PARSER));

cbor/src/test/java/com/fasterxml/jackson/dataformat/cbor/fuzz/CBORFuzz458_65768_NPETest.java

@@ -0,0 +1,38 @@
+package com.fasterxml.jackson.dataformat.cbor.fuzz;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.exc.StreamReadException;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import com.fasterxml.jackson.dataformat.cbor.CBORTestBase;
+
+public class CBORFuzz458_65768_NPETest extends CBORTestBase
+{
+    private final ObjectMapper MAPPER = cborMapper();
+
+    public void testInvalidText() throws Exception
+    {
+        final byte[] input = readResource("/data/clusterfuzz-cbor-65768.cbor");
+        try (JsonParser p = MAPPER.createParser(input)) {
+            try {
+                p.nextTextValue();
+                p.getIntValue();
+                p.nextTextValue();
+                p.nextTextValue();
+                p.nextTextValue();
+                p.nextTextValue();
+                p.nextTextValue();
+                p.nextTextValue();
+                p.nextTextValue();
+                p.nextTextValue();
+                p.nextTextValue();
+                p.getFloatValue();
+                p.getDecimalValue();
+                fail("Should not reach here (invalid input)");
+            } catch (StreamReadException e) {
+                verifyException(e, "No more values");
+            }
+        }
+    }
+}