diff --git a/ChangeLog b/ChangeLog
index de462a71..f03b2b13 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -35,6 +35,8 @@ ver. 0.10.5-dev-1 (20??/??/??) - development edition
 -----------
 
 ### Fixes
+* [compatibility] systemd backend: default flags changed to SYSTEM_ONLY(4), fixed in gh-2444 in order to ignore
+  user session files per default, so could prevent "Too many open files" errors on a lot of user sessions (see gh-2392)
 * [grave] fixed parsing of multi-line filters (`maxlines` > 1) together with systemd backend,
   now systemd-filter replaces newlines in message from systemd journal with `\n` (otherwise 
   multi-line parsing may be broken, because removal of matched string from multi-line buffer window
diff --git a/fail2ban/server/filtersystemd.py b/fail2ban/server/filtersystemd.py
index 5f17596a..be5a6dc4 100644
--- a/fail2ban/server/filtersystemd.py
+++ b/fail2ban/server/filtersystemd.py
@@ -86,10 +86,12 @@ class FilterSystemd(JournalFilter): # pragma: systemd no cover
 				files.extend(glob.glob(p))
 			args['files'] = list(set(files))
 
+		# Default flags is SYSTEM_ONLY(4). This would lead to ignore user session files,
+		# so can prevent "Too many open files" errors on a lot of user sessions (see gh-2392):
 		try:
 			args['flags'] = int(kwargs.pop('journalflags'))
 		except KeyError:
-			pass
+			args['flags'] = 4
 
 		return args