CVE-2026-80896

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

mshv: Fix race in mshv_irqfd_deassign

mshv_irqfd_deactivate() and the hlist traversal of pt_irqfds_list

require pt->pt_irqfds_lock to be held, but mshv_irqfd_deassign()

omits it. This races with the EPOLLHUP path in mshv_irqfd_wakeup(),

which does take the lock before calling mshv_irqfd_deactivate().

Additionally, mshv_irqfd_deactivate() uses hlist_del() which poisons

the node pointers rather than resetting them. Since

mshv_irqfd_is_active() relies on hlist_unhashed() (checks pprev ==

NULL), a poisoned node still appears active. If a concurrent path calls

mshv_irqfd_deactivate() again on the same irqfd, the guard fails to

prevent a double hlist_del() on poisoned pointers.

Fix both issues:

- Add the missing spin_lock_irq/spin_unlock_irq around the list

traversal in mshv_irqfd_deassign(), matching mshv_irqfd_release().

- Use hlist_del_init() instead of hlist_del() so the node is properly

marked as unhashed after

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References