PT-2026-64676 · Linux · Linux

CVE-2026-64455

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Published

2026-07-25

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Updated

2026-07-25

None

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In the Linux kernel, the following vulnerability has been resolved:
USB: chaoskey: Fix slab-use-after-free in chaoskey release()
The chaoskey driver has a use-after-free bug in its release routine. If the user closes the device file after the USB device has been unplugged, a debugging log statement will try to access the usb interface structure after it has been deallocated:
BUG: KASAN: slab-use-after-free in dev driver string (drivers/base/core.c:2406)
Read of size 8 at addr ffff888168e8a0b8 by task chaoskey raw re/10106

Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump stack lvl (lib/dump stack.c:94 lib/dump stack.c:120)
 print report (mm/kasan/report.c:378 mm/kasan/report.c:482)
 kasan report (mm/kasan/report.c:595)
 dev driver string (drivers/base/core.c:2406)
  dynamic dev dbg (lib/dynamic debug.c:906)
 chaoskey release (drivers/usb/misc/chaoskey.c:323)
  fput (fs/file table.c:510)
 fput close sync (fs/file table.c:615)
  x64 sys close (fs/open.c:1507 fs/open.c:1492 fs/open.c:1492)
 do syscall 64 (arch/x86/entry/syscall 64.c:63 arch/x86/entry/syscall 64.c:94)
 entry SYSCALL 64 after hwframe (arch/x86/entry/entry 64.S:121)
The driver's last reference to the interface structure is dropped in the chaoskey free() routine, so the code must not use the interface -- even in a debugging statement -- after that routine returns. (Exception: If we know that another reference is held by someone else, such as the device core while the disconnect routine runs, there's no problem. Thanks to Johan Hovold for pointing this out.)
Since the bad access is part of an unimportant debugging statement, we can fix the problem simply by removing the whole statement.
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Related Identifiers

CVE-2026-64455

Affected Products

Linux