diff --git a/CHANGELOG.md b/CHANGELOG.md
index 70f2c57..3af4399 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,12 @@ All notable changes to SeisComP are documented here.
         and origin for computing H.
     -   Consider correction term with exponential decay.
 
+## 6.4.2
+
+-   scqc
+    -   Fix performance issue which can result in 100% CPU usage so that
+        scqc cannot keep up with the input data rate.
+
 ## 6.4.1
 
 -   scevent