diff --git a/CHANGES b/CHANGES
index a143137297..99fcf27f8b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,8 @@
+3.3.0-dev.551 | 2020-11-17 15:01:04 -0700
+
+  * Added unit tests for regex fix (christina23)
+
+  * Improved regex for SMTP parsing (christina23)
 
 3.3.0-dev.548 | 2020-11-17 13:32:57 -0800
 
diff --git a/VERSION b/VERSION
index 4f3edfa80d..40e3177ad6 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.3.0-dev.548
+3.3.0-dev.551
diff --git a/scripts/base/utils/email.zeek b/scripts/base/utils/email.zeek
index 898ff9d6ec..903048eafd 100644
--- a/scripts/base/utils/email.zeek
+++ b/scripts/base/utils/email.zeek
@@ -59,7 +59,7 @@ function split_mime_email_addresses(line: string): set[string]
 	{
 	local output = string_set();
 
-	local addrs = find_all(line, /(\"[^"]*\")?[^,]+/);
+	local addrs = find_all(line, /(\"[^"]*\")?[^,]+@[^,]+/);
 	for ( part in addrs )
 		{
 		add output[strip(part)];
diff --git a/testing/btest/Baseline/scripts.base.utils.email/output b/testing/btest/Baseline/scripts.base.utils.email/output
index 853a2c5990..6955547403 100644
--- a/testing/btest/Baseline/scripts.base.utils.email/output
+++ b/testing/btest/Baseline/scripts.base.utils.email/output
@@ -19,3 +19,9 @@ three@example.com,
 one@example.com,
 two@example.com
 }
+john.smith@email.com
+[john.smith@email.com, jane.doe@email.com]
+{
+john.smith@email.com
+jane.doe@email.com
+}
diff --git a/testing/btest/scripts/base/utils/email.zeek b/testing/btest/scripts/base/utils/email.zeek
index f45064d1c6..5177ce8cb2 100644
--- a/testing/btest/scripts/base/utils/email.zeek
+++ b/testing/btest/scripts/base/utils/email.zeek
@@ -15,3 +15,7 @@ s = "ieje one@example.com, eifj two@example.com, asdf three@example.com, one@exa
 print extract_first_email_addr(s);
 print extract_email_addrs_vec(s);
 print extract_email_addrs_set(s);
+s = "\"Smith, John\" <john.smith@email.com>, \"Doe, Jane\" <jane.doe@email.com>";
+print extract_first_email_addr(s);
+print extract_email_addrs_vec(s);
+print extract_email_addrs_set(s);