diff --git a/Misc/NEWS b/Misc/NEWS
index ae2ce66..0d76a6e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -109,6 +109,8 @@
 Library
 -------
 
+- Issue #15777: Fix a refleak in _posixsubprocess.
+
 - Issue #15199: Fix JavaScript's default MIME type to application/javascript.
   Patch by Bohuslav Kabrda.
 
diff --git a/Modules/_posixsubprocess.c b/Modules/_posixsubprocess.c
index c93f537..59673f4 100644
--- a/Modules/_posixsubprocess.c
+++ b/Modules/_posixsubprocess.c
@@ -566,8 +566,10 @@
     }
 
     exec_array = _PySequence_BytesToCharpArray(executable_list);
-    if (!exec_array)
+    if (!exec_array) {
+        Py_XDECREF(gc_module);
         return NULL;
+    }
 
     /* Convert args and env into appropriate arguments for exec() */
     /* These conversions are done in the parent process to avoid allocating