diff -u apport-2.20.4/data/apport apport-2.20.4/data/apport
--- apport-2.20.4/data/apport
+++ apport-2.20.4/data/apport
@@ -15,6 +15,7 @@
 
 import sys, os, os.path, subprocess, time, traceback, pwd, io
 import signal, inspect, grp, fcntl, socket, atexit, array, struct
+import errno
 
 import apport, apport.fileutils
 
@@ -298,13 +299,20 @@
 
 
 def is_same_ns(pid, ns):
-    if not os.path.exists('/proc/self/ns/%s' % ns):
+    if not os.path.exists('/proc/self/ns/%s' % ns) or \
+            not os.path.exists('/proc/%s/ns/%s' % (pid, ns)):
         # If the namespace doesn't exist, then it's obviously shared
         return True
 
-    if os.readlink('/proc/%s/ns/%s' % (pid, ns)) == os.readlink('/proc/self/ns/%s' % ns):
-        # Check that the inode for both namespaces is the same
-        return True
+    try:
+        if os.readlink('/proc/%s/ns/%s' % (pid, ns)) == os.readlink('/proc/self/ns/%s' % ns):
+            # Check that the inode for both namespaces is the same
+            return True
+    except OSError as e:
+        if e.errno == errno.ENOENT:
+            pass
+        else:
+            raise
 
     return False
 
diff -u apport-2.20.4/debian/changelog apport-2.20.4/debian/changelog
--- apport-2.20.4/debian/changelog
+++ apport-2.20.4/debian/changelog
@@ -1,3 +1,11 @@
+apport (2.20.4-0ubuntu4.10) zesty-security; urgency=medium
+
+  * data/apport: add a second os.path.exists check to ensure we do not
+    receive a Traceback in is_container_id() and add an exception handler in
+    case either name space can not be found. (LP: #1733366)
+
+ -- Brian Murray <brian@ubuntu.com>  Wed, 13 Dec 2017 10:51:39 -0800
+
 apport (2.20.4-0ubuntu4.9) zesty; urgency=medium
 
   * bin/apport-cli: read until <enter> instead of a single character when # of