CVE-2026-90209: Linux

EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: s390/debug: Fix deadlock during unregister Unregistering an s390dbf debug area while one of the associated debugfs files is being written to can cause a deadlock: $ echo >.../vmur/level $ rmmod vmur =================================================== debugfs write debugfs_file_get() debug_unregister() mutex_lock(debug_mutex) debugfs_remove() wait for debugfs_file_put() debug_file_ops.write() debug_input() mutex_lock(debug_mutex) ==> DEADLOCK Fix this by splitting debug_unregister() into an s390dbf and debugfs part, and running only the s390dbf part with debug_mutex locked.

Affected products

• Linux Linux: from 5.4.146, before 5.5 (fixed in 5.5); from 5.10.65, before 5.11 (fixed in 5.11); from 5.13.17, before 5.14 (fixed in 5.14); from 5.14.4, before 5.15 (fixed in 5.15); from 5.15, before 5.15.221 (fixed in 5.15.221); from 5.16, before 6.1.188 (fixed in 6.1.188); …

Published 2026-09-17. Last modified 2026-09-17.