diff --git a/src/google/protobuf/compiler/parser.cc b/src/google/protobuf/compiler/parser.cc
index e5f42c4506..4381307624 100644
--- a/src/google/protobuf/compiler/parser.cc
+++ b/src/google/protobuf/compiler/parser.cc
@@ -310,9 +310,14 @@ bool Parser::ConsumeNumber(double* output, const char* error) {
                                      std::numeric_limits<uint64_t>::max(),
                                      &value)) {
       *output = value;
-    } else {
-      // out of int range, treat as double literal
-      *output = io::Tokenizer::ParseFloat(input_->current().text);
+    } else if (input_->current().text[0] == '0') {
+      // octal or hexadecimal; don't bother parsing as float
+      AddError("Integer out of range.");
+      // We still return true because we did, in fact, parse a number.
+    } else if (!io::Tokenizer::TryParseFloat(input_->current().text, output)) {
+      // out of int range, and not valid float? 🤷
+      AddError("Integer out of range.");
+      // We still return true because we did, in fact, parse a number.
     }
     input_->Next();
     return true;
diff --git a/src/google/protobuf/compiler/parser_unittest.cc b/src/google/protobuf/compiler/parser_unittest.cc
index 7685371c14..39d5b60744 100644
--- a/src/google/protobuf/compiler/parser_unittest.cc
+++ b/src/google/protobuf/compiler/parser_unittest.cc
@@ -1941,6 +1941,22 @@ TEST_F(ParserValidationErrorTest, FieldDefaultValueError) {
       "2:32: Enum type \"Baz\" has no value named \"NO_SUCH_VALUE\".\n");
 }
 
+TEST_F(ParserValidationErrorTest, FieldDefaultIntegerOutOfRange) {
+  ExpectHasErrors(
+      "message Foo {\n"
+      "  optional double bar = 1 [default = 0x10000000000000000];\n"
+      "}\n",
+      "1:37: Integer out of range.\n");
+}
+
+TEST_F(ParserValidationErrorTest, FieldOptionOutOfRange) {
+  ExpectHasErrors(
+      "message Foo {\n"
+      "  optional double bar = 1 [foo = 0x10000000000000000];\n"
+      "}\n",
+      "1:33: Integer out of range.\n");
+}
+
 TEST_F(ParserValidationErrorTest, FileOptionNameError) {
   ExpectHasValidationErrors(
       "option foo = 5;",
diff --git a/src/google/protobuf/io/tokenizer.cc b/src/google/protobuf/io/tokenizer.cc
index 7bc0820dd8..127fb5a402 100644
--- a/src/google/protobuf/io/tokenizer.cc
+++ b/src/google/protobuf/io/tokenizer.cc
@@ -1002,9 +1002,19 @@ bool Tokenizer::ParseInteger(const std::string& text, uint64_t max_value,
 }
 
 double Tokenizer::ParseFloat(const std::string& text) {
+  double result;
+  GOOGLE_LOG_IF(DFATAL,
+         !TryParseFloat(text, &result))
+      << " Tokenizer::ParseFloat() passed text that could not have been"
+         " tokenized as a float: "
+      << absl::CEscape(text);
+  return result;
+}
+
+bool Tokenizer::TryParseFloat(const std::string& text, double* result) {
   const char* start = text.c_str();
   char* end;
-  double result = NoLocaleStrtod(start, &end);
+  *result = NoLocaleStrtod(start, &end);
 
   // "1e" is not a valid float, but if the tokenizer reads it, it will
   // report an error but still return it as a valid token.  We need to
@@ -1020,12 +1030,7 @@ double Tokenizer::ParseFloat(const std::string& text) {
     ++end;
   }
 
-  GOOGLE_LOG_IF(DFATAL,
-         static_cast<size_t>(end - start) != text.size() || *start == '-')
-      << " Tokenizer::ParseFloat() passed text that could not have been"
-         " tokenized as a float: "
-      << absl::CEscape(text);
-  return result;
+  return static_cast<size_t>(end - start) == text.size() && *start != '-';
 }
 
 // Helper to append a Unicode code point to a string as UTF8, without bringing
diff --git a/src/google/protobuf/io/tokenizer.h b/src/google/protobuf/io/tokenizer.h
index cab1faf917..73877ccc24 100644
--- a/src/google/protobuf/io/tokenizer.h
+++ b/src/google/protobuf/io/tokenizer.h
@@ -214,6 +214,10 @@ class PROTOBUF_EXPORT Tokenizer {
   // result is undefined (possibly an assert failure).
   static double ParseFloat(const std::string& text);
 
+  // Parses given text as if it were a TYPE_FLOAT token.  Returns false if the
+  // given text is not actually a valid float literal.
+  static bool TryParseFloat(const std::string& text, double* result);
+
   // Parses a TYPE_STRING token.  This never fails, so long as the text actually
   // comes from a TYPE_STRING token parsed by Tokenizer.  If it doesn't, the
   // result is undefined (possibly an assert failure).