CVE-2026-90021
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_midi: initialize work in f_midi_alloc() f_midi_alloc initializes free_ref to 1 and it can only be incremented when a sound card is registered via f_midi_register_card(). f_midi_register_card() is only called in f_midi_bind() which actually performs INIT_WORK. If f_midi_bind() is never run, work is not initialized and the if condition in f_midi_free becomes true, this results in a warning later in __flush_work as work->func = 0. Fix this by moving INIT_WORK from f_midi_bind() to f_midi_alloc().
Affected versions
Linux kernel versions
5.4.291,
5.10.235,
5.12
and later are affected. Fixed in
6.12.110,
6.18.51,
7.2.5,
7.3-rc2
and their respective stable series.
References
4 totalFrequently asked questions
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What is CVE-2026-90021?
CVE-2026-90021 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.4.291 onward and has been patched in 6.12.110, 6.18.51, 7.2.5 and others. CVE-2026-90021 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-2026-90021?
Yes. CVE-2026-90021 has been patched. Fixed versions include 6.12.110, 6.18.51, 7.2.5 and others. If you are running Linux kernel 5.4.291 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-90021 actively exploited?
No. CVE-2026-90021 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.