--- a/src/google/protobuf/descriptor.cc	2022-03-14 15:16:40.588943398 -0700
+++ b/src/google/protobuf/descriptor.cc	2022-03-14 16:04:03.348461544 -0700
@@ -4002,6 +4002,11 @@
   // Use its file as the parent instead.
   if (parent == nullptr) parent = file_;
 
+  if (full_name.find('\0') != std::string::npos) {
+    AddError(full_name, proto, DescriptorPool::ErrorCollector::NAME,
+             "\"" + full_name + "\" contains null character.");
+    return false;
+  }
   if (tables_->AddSymbol(full_name, symbol)) {
     if (!file_tables_->AddAliasUnderParent(parent, name, symbol)) {
       // This is only possible if there was already an error adding something of
@@ -4041,6 +4046,11 @@
 void DescriptorBuilder::AddPackage(const std::string& name,
                                    const Message& proto,
                                    const FileDescriptor* file) {
+  if (name.find('\0') != std::string::npos) {
+    AddError(name, proto, DescriptorPool::ErrorCollector::NAME,
+             "\"" + name + "\" contains null character.");
+    return;
+  }
   if (tables_->AddSymbol(name, Symbol(file))) {
     // Success.  Also add parent package, if any.
     std::string::size_type dot_pos = name.find_last_of('.');
@@ -4354,6 +4364,12 @@
   }
   result->pool_ = pool_;
 
+  if (result->name().find('\0') != std::string::npos) {
+    AddError(result->name(), proto, DescriptorPool::ErrorCollector::NAME,
+             "\"" + result->name() + "\" contains null character.");
+    return nullptr;
+  }
+
   // Add to tables.
   if (!tables_->AddFile(result)) {
     AddError(proto.name(), proto, DescriptorPool::ErrorCollector::OTHER,
--- a/src/google/protobuf/descriptor_unittest.cc	2020-02-14 12:13:20.000000000 -0800
+++ b/src/google/protobuf/descriptor_unittest.cc	2022-03-14 15:18:13.727479837 -0700
@@ -3765,6 +3765,45 @@
       "foo.proto: foo.$: NAME: \"$\" is not a valid identifier.\n");
 }
 
+// 'str' is a static C-style string that may contain '\0'
+#define STATIC_STR(str) std::string((str), sizeof(str) - 1)
+
+TEST_F(ValidationErrorTest, NullCharSymbolName) {
+  BuildFileWithErrors(
+      "name: \"bar.proto\" "
+      "package: \"foo\""
+      "message_type { "
+      "  name: '\\000\\001\\013.Bar' "
+      "  field { name: \"foo\" number:  9 label:LABEL_OPTIONAL type:TYPE_INT32 "
+      "} "
+      "}",
+      STATIC_STR("bar.proto: foo.\0\x1\v.Bar: NAME: \"\0\x1\v.Bar\" is not a "
+                 "valid identifier.\nbar.proto: foo.\0\x1\v.Bar: NAME: "
+                 "\"\0\x1\v.Bar\" is not a valid identifier.\nbar.proto: "
+                 "foo.\0\x1\v.Bar: NAME: \"\0\x1\v.Bar\" is not a valid "
+                 "identifier.\nbar.proto: foo.\0\x1\v.Bar: NAME: "
+                 "\"\0\x1\v.Bar\" is not a valid identifier.\nbar.proto: "
+                 "foo.\0\x1\v.Bar.foo: NAME: \"foo.\0\x1\v.Bar.foo\" contains "
+                 "null character.\nbar.proto: foo.\0\x1\v.Bar: NAME: "
+                 "\"foo.\0\x1\v.Bar\" contains null character.\n"));
+}
+
+TEST_F(ValidationErrorTest, NullCharFileName) {
+  BuildFileWithErrors(
+      "name: \"bar\\000\\001\\013.proto\" "
+      "package: \"outer.foo\"",
+      STATIC_STR("bar\0\x1\v.proto: bar\0\x1\v.proto: NAME: "
+                 "\"bar\0\x1\v.proto\" contains null character.\n"));
+}
+
+TEST_F(ValidationErrorTest, NullCharPackageName) {
+  BuildFileWithErrors(
+      "name: \"bar.proto\" "
+      "package: \"\\000\\001\\013.\"",
+      STATIC_STR("bar.proto: \0\x1\v.: NAME: \"\0\x1\v.\" contains null "
+                 "character.\n"));
+}
+
 TEST_F(ValidationErrorTest, MissingFileName) {
   BuildFileWithErrors("",