Bug 2521376 (CVE-2026-74675)

Summary: CVE-2026-74675 kernel: vt: stabilize tty reference in kbd_keycode with tty_port_tty_get
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, 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. A race condition exists in the `kbd_keycode()` function within the virtual terminal (vt) subsystem. This occurs when `kbd_keycode()` attempts to read a terminal (tty) reference without properly acquiring and holding it, while the `con_shutdown()` function can concurrently clear the same reference. This timing vulnerability can lead to a use-after-free condition, potentially causing system instability or a denial of service (DoS) for a local attacker.
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Description OSIDB Bzimport 2026-08-22 15:42:29 UTC 
In the Linux kernel, the following vulnerability has been resolved:

vt: stabilize tty reference in kbd_keycode with tty_port_tty_get

kbd_keycode() reads vc->port.tty without acquiring a tty reference,
racing against con_shutdown() which clears port.tty under a different
lock. Use tty_port_tty_get()/tty_kref_put() to hold a proper reference
for the duration the tty pointer is needed.
Comment 1 gkamathe 2026-08-24 09:16:23 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082230-CVE-2026-74675-fffa@gregkh/T