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 bei…
Overview
CVE-2026-90209 is a known-severity vulnerability. It was published on September 17, 2026.
Technical 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.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
References
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Frequently asked questions
What is CVE-2026-90209?
CVE-2026-90209 is a known-severity vulnerability. It was published on September 17, 2026.
How severe is CVE-2026-90209?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-90209?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-90209?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-90209 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.