CVE-2026-68455

/// Technical description

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

liveupdate: validate session type before performing operation

The sessions ioctls are not applicable to all session types. PRESERVE_FD

is only applicable to outgoing sessions. RETRIEVE_FD and FINISH are only

valid for incoming session. Calling a incoming ioctl on an outgoing

session is invalid and can cause file handlers to run into unexpected

errors.

For example, a user can create a (outgoing) session, preserve a memfd,

and then immediately do a retrieve without doing a kexec in between.

This would result in memfd's retrieve handler to run. The handlers

expects to be called from a post-kexec context, and will try to do a

kho_restore_vmalloc() or kho_restore_folio() to try and restore memory.

KHO catches this (thanks to KHO_PAGE_MAGIC) and returns an error, but

since this is considered an internal error and KHO throws out a bunch of

WARN()s.

Associate a type with each ioctl op and validate the type in

luo_session_

/// 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