Bug 2507250 (CVE-2026-64474)

Summary: CVE-2026-64474 kernel: vfio: prevent infinite loop in vfio_mig_get_next_state() on blocked arc
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Virtual Function I/O (VFIO) device migration feature. The `vfio_mig_get_next_state()` function, responsible for managing device migration states, contains an infinite loop. This occurs when processing certain blocked transitions, causing the system to hold a driver state mutex indefinitely. This can lead to a soft lockup of the system and potentially a kernel panic, resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-07-25 10:12:50 UTC 
In the Linux kernel, the following vulnerability has been resolved:

vfio: prevent infinite loop in vfio_mig_get_next_state() on blocked arc

vfio_mig_get_next_state() walks vfio_from_fsm_table[] one step at a time,
looping to skip optional states the device does not support until
*next_fsm is supported. A blocked transition is encoded as
VFIO_DEVICE_STATE_ERROR, which the trailing return reports as -EINVAL.

The skip loop does not account for the ERROR sentinel.
state_flags_table[ERROR] is ~0U and vfio_from_fsm_table[ERROR][*] is
ERROR, so once *next_fsm becomes ERROR the loop condition stays true and
*next_fsm never changes. The blocked arcs STOP_COPY -> PRE_COPY and
STOP_COPY -> PRE_COPY_P2P map to ERROR yet pass the support check on a
precopy-capable device, causing the loop to spin forever while holding
the driver state mutex. This can result in a soft lockup, and a panic
with softlockup_panic set.

Terminate the skip loop on the ERROR sentinel so a blocked transition
falls through to the existing return and reports -EINVAL.
Comment 1 TEJ RATHI 2026-07-29 07:13:55 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072546-CVE-2026-64474-a4d3@gregkh/T