Bug 2536561 (CVE-2026-90158)

Summary: CVE-2026-90158 kernel: m68k: nfcon: Do not call console_is_registered() in nfcon_device()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's m68k nfcon module. A deadlock can occur when the `show_cons_active()` function calls the `.device()` method while holding the `console_list_lock`, and the `console_is_registered()` function attempts to acquire the same lock. This contention for the lock can lead to a system deadlock, effectively causing a Denial of Service (DoS) for affected systems.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-17 18:24:48 UTC
In the Linux kernel, the following vulnerability has been resolved:

m68k: nfcon: Do not call console_is_registered() in nfcon_device()

Since 7c2af0f634f1 ("tty: tty_io: use console_list_lock for list
synchronization") show_cons_active() calls the .device() method under
the console_list_lock, but console_is_registered() tries to acquire
console_list_lock as well, causing a deadlock.  It should not be
necessary to check console_is_registered() here since the function
should not be called in the fist place when the console is not
registered.