diff --git a/README.md b/README.md
index 2762b48..4b60f9e 100644
--- a/README.md
+++ b/README.md
@@ -252,6 +252,9 @@ For convenience, a web front-end on top of the command-line tool is available at
 
 ## ChangeLog
 
+### v3.9.1-dev
+ - Fixed a perhaps rare crash when performing connection rate tests during standard audits.
+
 ### v3.9.0 (2026-07-04)
  - BIG THANKS to [realmiwi](https://github.com/realmiwi) for being the project's *very first sponsor!!*
  - Added support for Python 3.14.
diff --git a/src/ssh_audit/dheat.py b/src/ssh_audit/dheat.py
index 82cf060..77ad437 100644
--- a/src/ssh_audit/dheat.py
+++ b/src/ssh_audit/dheat.py
@@ -324,7 +324,8 @@ class DHEat:
             except OSError:
                 pass
 
-            del socket_dict[s]
+            if s in socket_dict:
+                del socket_dict[s]
 
         # Check if this platform has socket.AF_UNIX. Windows does not.
         has_af_unix = hasattr(socket, 'AF_UNIX')