diff --git a/Lib/webbrowser.py b/Lib/webbrowser.py
index 8617425..94d4ad4 100644
--- a/Lib/webbrowser.py
+++ b/Lib/webbrowser.py
@@ -230,7 +230,7 @@
         cmdline = [self.name] + raise_opt + args
 
         if remote or self.background:
-            inout = io.open(os.devnull, "r+")
+            inout = subprocess.DEVNULL
         else:
             # for TTY browsers, we need stdin/out
             inout = None
@@ -354,7 +354,7 @@
         else:
             action = "openURL"
 
-        devnull = io.open(os.devnull, "r+")
+        devnull = subprocess.DEVNULL
         # if possible, put browser in separate process group, so
         # keyboard interrupts don't affect browser as well as Python
         setsid = getattr(os, 'setsid', None)
diff --git a/Misc/NEWS b/Misc/NEWS
index 93bc1db..0463aa2 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -21,6 +21,9 @@
 Library
 -------
 
+- Issue #15447: Use subprocess.DEVNULL in webbrowser, instead of opening
+  os.devnull explicitly and leaving it open.
+
 - Issue #15509: webbrowser.UnixBrowser no longer passes empty arguments to
   Popen when %action substitutions produce empty strings.