Add anchor for incoming email regex, closes 44989ccr/regexp_anchor

3 files changed, 8 insertions, 1 deletions

diff --git a/changelogs/unreleased/ccr-incoming-email-regex-anchor.yml b/changelogs/unreleased/ccr-incoming-email-regex-anchor.yml
new file mode 100644
index 00000000000..a0d787e570e
--- /dev/null
+++ b/changelogs/unreleased/ccr-incoming-email-regex-anchor.yml
@@ -0,0 +1,3 @@
+title: Add anchor for incoming email regex
+merge_request: !18917
+type: added
diff --git a/lib/gitlab/incoming_email.rb b/lib/gitlab/incoming_email.rb
index c9122a23568..d323cb9dadf 100644
--- a/lib/gitlab/incoming_email.rb
+++ b/lib/gitlab/incoming_email.rb
@@ -57,7 +57,7 @@ module Gitlab
 
         regex = Regexp.escape(wildcard_address)
         regex = regex.sub(Regexp.escape(WILDCARD_PLACEHOLDER), '(.+)')
-        Regexp.new(regex).freeze
+        Regexp.new(/\A#{regex}\z/).freeze
       end
     end
   end
diff --git a/spec/lib/gitlab/incoming_email_spec.rb b/spec/lib/gitlab/incoming_email_spec.rb
index ad087f42e06..4c0c3fcbcc7 100644
--- a/spec/lib/gitlab/incoming_email_spec.rb
+++ b/spec/lib/gitlab/incoming_email_spec.rb
@@ -83,6 +83,10 @@ describe Gitlab::IncomingEmail do
     it "returns reply key" do
       expect(described_class.key_from_address("replies+key@example.com")).to eq("key")
     end
+
+    it 'does not match emails with extra bits' do
+      expect(described_class.key_from_address('somereplies+somekey@example.com.someotherdomain.com')).to be nil
+    end
   end
 
   context 'self.key_from_fallback_message_id' do