diff --git a/Lib/email/_parseaddr.py b/Lib/email/_parseaddr.py
index 690db2c..dc49d2e 100644
--- a/Lib/email/_parseaddr.py
+++ b/Lib/email/_parseaddr.py
@@ -336,7 +336,12 @@ class AddrlistClass:
         aslist.append('@')
         self.pos += 1
         self.gotonext()
-        return EMPTYSTRING.join(aslist) + self.getdomain()
+        domain = self.getdomain()
+        if not domain:
+            # Invalid domain, return an empty address instead of returning a
+            # local part to denote failed parsing.
+            return EMPTYSTRING
+        return EMPTYSTRING.join(aslist) + domain
 
     def getdomain(self):
         """Get the complete domain name from an address."""
@@ -351,6 +356,10 @@ class AddrlistClass:
             elif self.field[self.pos] == '.':
                 self.pos += 1
                 sdlist.append('.')
+            elif self.field[self.pos] == '@':
+                # bpo-34155: Don't parse domains with two `@` like
+                # `a@malicious.org@important.com`.
+                return EMPTYSTRING
             elif self.field[self.pos] in self.atomends:
                 break
             else:
diff --git a/Lib/email/test/test_email.py b/Lib/email/test/test_email.py
index b32da9d..1739033 100644
--- a/Lib/email/test/test_email.py
+++ b/Lib/email/test/test_email.py
@@ -2308,6 +2308,20 @@ class TestMiscellaneous(TestEmailBase):
         self.assertEqual(Utils.parseaddr('<>'), ('', ''))
         self.assertEqual(Utils.formataddr(Utils.parseaddr('<>')), '')
 
+    def test_parseaddr_multiple_domains(self):
+        self.assertEqual(
+            Utils.parseaddr('a@b@c'),
+            ('', '')
+        )
+        self.assertEqual(
+            Utils.parseaddr('a@b.c@c'),
+            ('', '')
+        )
+        self.assertEqual(
+            Utils.parseaddr('a@172.17.0.1@c'),
+            ('', '')
+        )
+
     def test_noquote_dump(self):
         self.assertEqual(
             Utils.formataddr(('A Silly Person', 'person@dom.ain')),