diff --git a/conformance/binary_json_conformance_suite.cc b/conformance/binary_json_conformance_suite.cc
index ede4710cc6..cdf63cba9e 100644
--- a/conformance/binary_json_conformance_suite.cc
+++ b/conformance/binary_json_conformance_suite.cc
@@ -2303,7 +2303,8 @@ void BinaryAndJsonConformanceSuiteImpl<
                             R"({"optionalInt64": "-9223372036854775809"})");
   ExpectParseFailureForJson("Uint64FieldTooLarge", REQUIRED,
                             R"({"optionalUint64": "18446744073709551616"})");
-  // Parser reject non-integer numeric values as well.
+
+  // Parser reject non-integer numeric values.
   ExpectParseFailureForJson("Int32FieldNotInteger", REQUIRED,
                             R"({"optionalInt32": 0.5})");
   ExpectParseFailureForJson("Uint32FieldNotInteger", REQUIRED,
@@ -2313,6 +2314,16 @@ void BinaryAndJsonConformanceSuiteImpl<
   ExpectParseFailureForJson("Uint64FieldNotInteger", REQUIRED,
                             R"({"optionalUint64": "0.5"})");
 
+  // Parser reject empty string values.
+  ExpectParseFailureForJson("Int32FieldEmptyString", REQUIRED,
+                            R"({"optionalInt32": ""})");
+  ExpectParseFailureForJson("Uint32FieldEmptyString", REQUIRED,
+                            R"({"optionalUint32": ""})");
+  ExpectParseFailureForJson("Int64FieldEmptyString", REQUIRED,
+                            R"({"optionalInt64": ""})");
+  ExpectParseFailureForJson("Uint64FieldEmptyString", REQUIRED,
+                            R"({"optionalUint64": ""})");
+
   // Integers but represented as float values are accepted.
   RunValidJsonTest("Int32FieldFloatTrailingZero", REQUIRED,
                    R"({"optionalInt32": 100000.000})",
@@ -2436,12 +2447,17 @@ void BinaryAndJsonConformanceSuiteImpl<
                             R"({"optionalFloat": Infinity})");
   ExpectParseFailureForJson("FloatFieldNegativeInfinityNotQuoted", RECOMMENDED,
                             R"({"optionalFloat": -Infinity})");
+
   // Parsers should reject out-of-bound values.
   ExpectParseFailureForJson("FloatFieldTooSmall", REQUIRED,
                             R"({"optionalFloat": -3.502823e+38})");
   ExpectParseFailureForJson("FloatFieldTooLarge", REQUIRED,
                             R"({"optionalFloat": 3.502823e+38})");
 
+  // Parsers should reject empty string values.
+  ExpectParseFailureForJson("FloatFieldEmptyString", REQUIRED,
+                            R"({"optionalFloat": ""})");
+
   // Double fields.
   RunValidJsonTest("DoubleFieldMinPositiveValue", REQUIRED,
                    R"({"optionalDouble": 2.22507e-308})",
@@ -2494,6 +2510,10 @@ void BinaryAndJsonConformanceSuiteImpl<
   ExpectParseFailureForJson("DoubleFieldTooLarge", REQUIRED,
                             R"({"optionalDouble": +1.89769e+308})");
 
+  // Parsers should reject empty string values.
+  ExpectParseFailureForJson("DoubleFieldEmptyString", REQUIRED,
+                            R"({"optionalDouble": ""})");
+
   // Enum fields.
   RunValidJsonTest("EnumField", REQUIRED, R"({"optionalNestedEnum": "FOO"})",
                    "optional_nested_enum: FOO");
diff --git a/conformance/failure_list_jruby_ffi.txt b/conformance/failure_list_jruby_ffi.txt
index e69de29bb2..81ebd2e020 100644
--- a/conformance/failure_list_jruby_ffi.txt
+++ b/conformance/failure_list_jruby_ffi.txt
@@ -0,0 +1,24 @@
+Required.Editions_Proto2.JsonInput.DoubleFieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.FloatFieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Int32FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Int64FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Uint32FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Uint64FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.DoubleFieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.FloatFieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Int32FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Int64FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Uint32FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Uint64FieldEmptyString # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.DoubleFieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.FloatFieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Int32FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Int64FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Uint32FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Uint64FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.DoubleFieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.FloatFieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Int32FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Int64FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Uint32FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Uint64FieldEmptyString          # Should have failed to parse, but didn't.
diff --git a/conformance/failure_list_php_c.txt b/conformance/failure_list_php_c.txt
index df662c320a..e9853d8d2f 100644
--- a/conformance/failure_list_php_c.txt
+++ b/conformance/failure_list_php_c.txt
@@ -1,4 +1,28 @@
 Recommended.Proto2.JsonInput.FieldNameExtension.Validator
+Required.Editions_Proto2.JsonInput.DoubleFieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.FloatFieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Int32FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Int64FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Uint32FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Uint64FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.DoubleFieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.FloatFieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Int32FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Int64FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Uint32FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Uint64FieldEmptyString # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.DoubleFieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.FloatFieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Int32FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Int64FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Uint32FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Uint64FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.DoubleFieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.FloatFieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Int32FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Int64FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Uint32FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Uint64FieldEmptyString          # Should have failed to parse, but didn't.
 Required.Proto2.JsonInput.BoolFieldFalse.JsonOutput
 Required.Proto2.JsonInput.BoolFieldFalse.ProtobufOutput
 Required.Proto2.JsonInput.EnumField.JsonOutput
diff --git a/conformance/failure_list_ruby.txt b/conformance/failure_list_ruby.txt
index e69de29bb2..81ebd2e020 100644
--- a/conformance/failure_list_ruby.txt
+++ b/conformance/failure_list_ruby.txt
@@ -0,0 +1,24 @@
+Required.Editions_Proto2.JsonInput.DoubleFieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.FloatFieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Int32FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Int64FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Uint32FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Uint64FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.DoubleFieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.FloatFieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Int32FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Int64FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Uint32FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Uint64FieldEmptyString # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.DoubleFieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.FloatFieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Int32FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Int64FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Uint32FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Uint64FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.DoubleFieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.FloatFieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Int32FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Int64FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Uint32FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Uint64FieldEmptyString          # Should have failed to parse, but didn't.
diff --git a/upb/conformance/conformance_upb_failures.txt b/upb/conformance/conformance_upb_failures.txt
index e69de29bb2..81ebd2e020 100644
--- a/upb/conformance/conformance_upb_failures.txt
+++ b/upb/conformance/conformance_upb_failures.txt
@@ -0,0 +1,24 @@
+Required.Editions_Proto2.JsonInput.DoubleFieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.FloatFieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Int32FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Int64FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Uint32FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto2.JsonInput.Uint64FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.DoubleFieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.FloatFieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Int32FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Int64FieldEmptyString  # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Uint32FieldEmptyString # Should have failed to parse, but didn't.
+Required.Editions_Proto3.JsonInput.Uint64FieldEmptyString # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.DoubleFieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.FloatFieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Int32FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Int64FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Uint32FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto2.JsonInput.Uint64FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.DoubleFieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.FloatFieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Int32FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Int64FieldEmptyString           # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Uint32FieldEmptyString          # Should have failed to parse, but didn't.
+Required.Proto3.JsonInput.Uint64FieldEmptyString          # Should have failed to parse, but didn't.