diff --git a/tests/mtd_mapper/Makefile b/tests/mtd_mapper/Makefile
index 599f5792d9..337a9fd7ef 100644
--- a/tests/mtd_mapper/Makefile
+++ b/tests/mtd_mapper/Makefile
@@ -3,4 +3,7 @@ include ../Makefile.tests_common
 USEMODULE += mtd_mapper
 USEMODULE += embunit
 
+# disabling due to unknown failure. See #15123.
+TEST_ON_CI_BLACKLIST += esp32-wroom-32
+
 include $(RIOTBASE)/Makefile.include
diff --git a/tests/pkg_littlefs/Makefile b/tests/pkg_littlefs/Makefile
index 0cff046cf2..4c4cae6edc 100644
--- a/tests/pkg_littlefs/Makefile
+++ b/tests/pkg_littlefs/Makefile
@@ -3,4 +3,7 @@ include ../Makefile.tests_common
 USEMODULE += littlefs
 USEMODULE += embunit
 
+# disabling due to unknown failure. See #15123.
+TEST_ON_CI_BLACKLIST += esp32-wroom-32
+
 include $(RIOTBASE)/Makefile.include
diff --git a/tests/pkg_littlefs2/Makefile b/tests/pkg_littlefs2/Makefile
index 07eef1db2c..89b9b91a29 100644
--- a/tests/pkg_littlefs2/Makefile
+++ b/tests/pkg_littlefs2/Makefile
@@ -3,4 +3,7 @@ include ../Makefile.tests_common
 USEPKG += littlefs2
 USEMODULE += embunit
 
+# disabling due to unknown failure. See #15123.
+TEST_ON_CI_BLACKLIST += esp32-wroom-32
+
 include $(RIOTBASE)/Makefile.include
diff --git a/tests/pkg_spiffs/Makefile b/tests/pkg_spiffs/Makefile
index d52effe4bf..a0354076bf 100644
--- a/tests/pkg_spiffs/Makefile
+++ b/tests/pkg_spiffs/Makefile
@@ -3,4 +3,7 @@ include ../Makefile.tests_common
 USEMODULE += spiffs
 USEMODULE += embunit
 
+# disabling due to unknown failure. See #15123.
+TEST_ON_CI_BLACKLIST += esp32-wroom-32
+
 include $(RIOTBASE)/Makefile.include