CVE-2026-90209

Description

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.

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EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/183f8f6d64bb0510070c856b9927618c53014a7b https://git.kernel.org/stable/c/445c31ac638fd1af203d79bdf25fc0cb3149fbbc https://git.kernel.org/stable/c/45bb341d1b73eb293e0dd43d9b72bbc8b615d0ba https://git.kernel.org/stable/c/54e1259b75d6402a1d0cfb822b9bb2c507e53dab https://git.kernel.org/stable/c/5d83f3faa3fb7f23f298cfd40382611999de5d1d https://git.kernel.org/stable/c/a08b70ed2d1ec907353a72f15163b8e34ff4b2f8 https://git.kernel.org/stable/c/a214c3dacc779b2afcb0ac9c8001e45ee4ffb2ed

Frequently Asked Questions

What is 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.

How do I check if I'm vulnerable to CVE-2026-90209? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.