diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 449112319..49bac71e6 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,9 @@
+2015-11-18  Corinna Vinschen  <corinna@vinschen.de>
+
+	* sec_acl.cc (get_posix_access): Skip merging permissions if current
+	user has rwx permissions anywa, or if the sum of all group and other
+	permissions is less than or equal to the user's permissions.
+
 2015-11-18  Corinna Vinschen  <corinna@vinschen.de>
 
 	* sec_acl.cc (get_posix_access): Fix computation of effective user
diff --git a/winsup/cygwin/sec_acl.cc b/winsup/cygwin/sec_acl.cc
index a9e1dea5f..f632410ee 100644
--- a/winsup/cygwin/sec_acl.cc
+++ b/winsup/cygwin/sec_acl.cc
@@ -1019,8 +1019,17 @@ get_posix_access (PSECURITY_DESCRIPTOR psd,
 	  {
 	    mode_t perm;
 
-	    /* If we use the Windows user DB, utilize Authz to make sure all
-	       user permissions are correctly reflecting the Windows
+	    /* Don't merge if the user already has all permissions, or... */
+	    if (lacl[idx].a_perm == S_IRWXO)
+	      continue;
+	    /* ...if the sum of perms is less than or equal the user's perms. */
+	    perm = lacl[idx].a_perm
+		   | (has_class_perm ? class_perm : lacl[1].a_perm)
+		   | lacl[2].a_perm;
+	    if (perm == lacl[idx].a_perm)
+	      continue;
+	    /* Otherwise, if we use the Windows user DB, utilize Authz to make
+	       sure all user permissions are correctly reflecting the Windows
 	       permissions. */
 	    if (cygheap->pg.nss_pwd_db ()
 		&& authz_get_user_attribute (&perm, psd, aclsid[idx]))