diff --git a/ext/json/ext/parser/parser.c b/ext/json/ext/parser/parser.c
index 288521e1c..d86c347ad 100644
--- a/ext/json/ext/parser/parser.c
+++ b/ext/json/ext/parser/parser.c
@@ -1169,11 +1169,11 @@ static inline VALUE json_decode_float(JSON_ParserConfig *config, uint64_t mantis
         return rb_funcallv(config->decimal_class, config->decimal_method_id, 1, &text);
     }
 
-    if (RB_UNLIKELY(exponent > INT32_MAX)) {
+    if (RB_UNLIKELY(exponent >= (int64_t)INT32_MAX)) {
         return negative ? CMinusInfinity : CInfinity;
     }
 
-    if (RB_UNLIKELY(exponent < INT32_MIN)) {
+    if (RB_UNLIKELY(exponent <= INT32_MIN)) {
         return rb_float_new(negative ? -0.0 : 0.0);
     }
 
@@ -1514,7 +1514,7 @@ static inline VALUE json_parse_number(JSON_ParserState *state, JSON_ParserConfig
         }
 
         if (RB_UNLIKELY(exponent_digits >= 20 || abs_exponent > (uint64_t)INT64_MAX)) {
-            exponent = negative_exponent ? INT64_MIN : INT64_MAX;
+            exponent = negative_exponent ? INT32_MIN : INT32_MAX;
         } else {
             exponent = negative_exponent ? -(int64_t)abs_exponent : (int64_t)abs_exponent;
         }
diff --git a/java/src/json/ext/Parser.java b/java/src/json/ext/Parser.java
index 88bc054ef..6fa5d4383 100644
--- a/java/src/json/ext/Parser.java
+++ b/java/src/json/ext/Parser.java
@@ -634,7 +634,7 @@ private IRubyObject parseNumber(int numberStart, byte first, boolean negative) {
                 }
 
                 if (exponent_digits >= 20 || Long.compareUnsigned(abs_exponent, Long.MAX_VALUE) > 0) {
-                    exponent = negative_exponent ? Long.MIN_VALUE : Long.MAX_VALUE;
+                    exponent = negative_exponent ? Integer.MIN_VALUE : Integer.MAX_VALUE;
                 } else {
                     exponent = negative_exponent ? -abs_exponent : abs_exponent;
                 }
@@ -655,8 +655,8 @@ private IRubyObject parseNumber(int numberStart, byte first, boolean negative) {
 
         IRubyObject decodeFloat(ThreadContext context, long mantissa, int mantissa_digits, long exponent, boolean negative, int start) {
             if (config.decimalClass != null) return config.decimalFactory.apply(context, absSubSequence(start, cursor));
-            if (exponent > Integer.MAX_VALUE) return getConstant(negative ? CONST_MINUS_INFINITY : CONST_INFINITY);
-            if (exponent < Integer.MIN_VALUE) return RubyFloat.newFloat(context.runtime, negative ? -0.0 : 0.0);
+            if (exponent >= Integer.MAX_VALUE) return getConstant(negative ? CONST_MINUS_INFINITY : CONST_INFINITY);
+            if (exponent <= Integer.MIN_VALUE) return RubyFloat.newFloat(context.runtime, negative ? -0.0 : 0.0);
 
             // Ryu has rounding issues with subnormals around 1e-310 (< 2.225e-308)
             if (mantissa_digits > 17 || mantissa_digits + exponent < -307) {
diff --git a/test/json/json_parser_test.rb b/test/json/json_parser_test.rb
index 75e99904d..47d84b398 100644
--- a/test/json/json_parser_test.rb
+++ b/test/json/json_parser_test.rb
@@ -147,6 +147,12 @@ def test_parse_numbers
     assert_raise(ParserError) { parse('-Infinity') }
     assert_equal(-1.0/0, parse('-Infinity', allow_nan: true))
     capture_output { assert_equal(Float::INFINITY, parse("23456789012E666")) }
+
+    assert_parse_float "1.5e-99999999999999999999"
+    assert_parse_float "1.5e-9223372036854775808"
+    assert_parse_float "0.0e-99999999999999999999"
+    assert_parse_float "-1.5e-99999999999999999999"
+    assert_parse_float "123.456e-18446744073709551615"
   end
 
   INTEGER_FAST_PATH_BOUNDARIES = [
@@ -1084,6 +1090,10 @@ def encode(*)
 
   private
 
+  def assert_parse_float(float_str)
+    assert_equal Float(float_str), JSON.parse(float_str)
+  end
+
   def assert_equal_float(expected, actual, delta = 1e-2)
     Array === expected and expected = expected.first
     Array === actual and actual = actual.first