diff --git a/NEWS b/NEWS
index d196df9bd..19e605ae7 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,6 @@
-1.5.18.dev0
+1.5.18
  * #389: Fix "message too long" error when logging to rsyslog.
+ * #440: Fix traceback that can occur when dumping a database.
 
 1.5.17
  * #437: Fix error when configuration file contains "umask" option.
diff --git a/borgmatic/execute.py b/borgmatic/execute.py
index db6da6408..a6741c904 100644
--- a/borgmatic/execute.py
+++ b/borgmatic/execute.py
@@ -81,6 +81,7 @@ def log_outputs(processes, exclude_stdouts, output_log_level, borg_local_path):
                     for other_process in processes:
                         if (
                             other_process.poll() is None
+                            and other_process.stdout
                             and other_process.stdout not in output_buffers
                         ):
                             # Add the process's output to output_buffers to ensure it'll get read.
@@ -138,10 +139,10 @@ def log_outputs(processes, exclude_stdouts, output_log_level, borg_local_path):
         if not output_buffer:
             continue
 
-        while True:
+        while True:  # pragma: no cover
             remaining_output = output_buffer.readline().rstrip().decode()
 
-            if not remaining_output:  # pragma: no cover
+            if not remaining_output:
                 break
 
             logger.log(output_log_level, remaining_output)
diff --git a/setup.py b/setup.py
index 5f5330fa1..49b93d012 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,6 @@
 from setuptools import find_packages, setup
 
-VERSION = '1.5.18.dev0'
+VERSION = '1.5.18'
 
 
 setup(
diff --git a/tests/integration/test_execute.py b/tests/integration/test_execute.py
index 7320658d5..51aa5f434 100644
--- a/tests/integration/test_execute.py
+++ b/tests/integration/test_execute.py
@@ -162,6 +162,37 @@ def test_log_outputs_vents_other_processes_when_one_exits():
     )
 
 
+def test_log_outputs_does_not_error_when_one_process_exits():
+    flexmock(module.logger).should_receive('log')
+    flexmock(module).should_receive('command_for_process').and_return('grep')
+
+    process = subprocess.Popen(
+        [
+            sys.executable,
+            '-c',
+            "import random, string; print(''.join(random.choice(string.ascii_letters) for _ in range(40000)))",
+        ],
+        stdout=None,  # Specifically test the case of a process without stdout captured.
+        stderr=None,
+    )
+    other_process = subprocess.Popen(
+        ['true'], stdin=process.stdout, stdout=subprocess.PIPE, stderr=subprocess.STDOUT
+    )
+    flexmock(module).should_receive('output_buffer_for_process').with_args(
+        process, (process.stdout,)
+    ).and_return(process.stderr)
+    flexmock(module).should_receive('output_buffer_for_process').with_args(
+        other_process, (process.stdout,)
+    ).and_return(other_process.stdout)
+
+    module.log_outputs(
+        (process, other_process),
+        exclude_stdouts=(process.stdout,),
+        output_log_level=logging.INFO,
+        borg_local_path='borg',
+    )
+
+
 def test_log_outputs_truncates_long_error_output():
     flexmock(module).ERROR_OUTPUT_MAX_LINE_COUNT = 0
     flexmock(module.logger).should_receive('log')