CVE-2026-90209
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 versions
Linux kernel versions
5.4.146,
5.10.65,
5.13.17,
5.14.4,
5.15
and later are affected. Fixed in
5.15.221,
6.1.188,
6.6.157,
6.12.110,
6.18.52,
7.2.6,
7.3-rc1
and their respective stable series.
References
7 totalFrequently asked questions
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What is CVE-2026-90209?
CVE-2026-90209 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.4.146 onward and has been patched in 5.15.221, 6.1.188, 6.6.157 and others. CVE-2026-90209 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-90209?
Yes. CVE-2026-90209 has been patched. Fixed versions include 5.15.221, 6.1.188, 6.6.157 and others. If you are running Linux kernel 5.4.146 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-90209 actively exploited?
No. CVE-2026-90209 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.