diff --git a/security/certverifier/tests/gtest/CTTestUtils.cpp b/security/certverifier/tests/gtest/CTTestUtils.cpp
index e3436817ee89..117165ca79aa 100644
--- a/security/certverifier/tests/gtest/CTTestUtils.cpp
+++ b/security/certverifier/tests/gtest/CTTestUtils.cpp
@@ -125,6 +125,7 @@ CharToByte(char c)
     return c - 'A' + 10;
   }
   MOZ_RELEASE_ASSERT(false);
+  return 0;
 }
 
 static Buffer