diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index db760bac7..9a6e9eb8f 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -1045,11 +1045,6 @@ parameters:
 			count: 1
 			path: program/lib/Roundcube/rcube_imap.php
 
-		-
-			message: "#^Variable \\$n might not be defined\\.$#"
-			count: 1
-			path: program/lib/Roundcube/rcube_imap.php
-
 		-
 			message: "#^Call to function is_object\\(\\) with rcube_message_header will always evaluate to true\\.$#"
 			count: 1
@@ -1160,16 +1155,6 @@ parameters:
 			count: 3
 			path: program/lib/Roundcube/rcube_imap_generic.php
 
-		-
-			message: "#^Variable \\$entries might not be defined\\.$#"
-			count: 1
-			path: program/lib/Roundcube/rcube_imap_generic.php
-
-		-
-			message: "#^Variable \\$pos might not be defined\\.$#"
-			count: 2
-			path: program/lib/Roundcube/rcube_imap_generic.php
-
 		-
 			message: "#^Call to function is_array\\(\\) with string will always evaluate to false\\.$#"
 			count: 1
@@ -1405,36 +1390,11 @@ parameters:
 			count: 1
 			path: program/lib/Roundcube/rcube_string_replacer.php
 
-		-
-			message: "#^Variable \\$i might not be defined\\.$#"
-			count: 2
-			path: program/lib/Roundcube/rcube_string_replacer.php
-
-		-
-			message: "#^Variable \\$len might not be defined\\.$#"
-			count: 2
-			path: program/lib/Roundcube/rcube_string_replacer.php
-
 		-
 			message: "#^Call to function is_array\\(\\) with non\\-empty\\-array will always evaluate to true\\.$#"
 			count: 1
 			path: program/lib/Roundcube/rcube_text2html.php
 
-		-
-			message: "#^Variable \\$m might not be defined\\.$#"
-			count: 1
-			path: program/lib/Roundcube/rcube_tnef_decoder.php
-
-		-
-			message: "#^Variable \\$i might not be defined\\.$#"
-			count: 2
-			path: program/lib/Roundcube/rcube_utils.php
-
-		-
-			message: "#^Variable \\$ts might not be defined\\.$#"
-			count: 1
-			path: program/lib/Roundcube/rcube_utils.php
-
 		-
 			message: "#^Call to function is_array\\(\\) with array will always evaluate to true\\.$#"
 			count: 2
@@ -1470,11 +1430,6 @@ parameters:
 			count: 1
 			path: program/lib/Roundcube/rcube_washtml.php
 
-		-
-			message: "#^Variable \\$p might not be defined\\.$#"
-			count: 1
-			path: program/lib/Roundcube/rcube_washtml.php
-
 		-
 			message: "#^Parameter \\#1 \\$browser \\(Tests\\\\Browser\\\\Browser\\) of method Tests\\\\Browser\\\\Components\\\\App\\:\\:assert\\(\\) should be contravariant with parameter \\$browser \\(Laravel\\\\Dusk\\\\Browser\\) of method Laravel\\\\Dusk\\\\Component\\:\\:assert\\(\\)$#"
 			count: 1
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 2b40b1fa6..1e1761219 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -14,6 +14,7 @@ parameters:
         - '~^Only booleans are allowed in .+, .+ given( on the (left|right) side)?\.~'
         - '~^Variable (static )?(property access|method call) on .+\.~'
         - '~^Variable variables are not allowed.~'
+        - '~^Variable .* might not be defined\.~'
         # relax strict rules - move to phpstan baseline once almost all l6 errors are fixed
         - '~^Dynamic call to static method .+\.~' # TODO in https://github.com/roundcube/roundcubemail/pull/9314
         - '~^Construct empty\(\) is not allowed\. Use more strict comparison\.~'