CVE-2026-68455

Received Received - Intake

Session Type Validation Bypass in Linux Kernel

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

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_ioctl() before dispatching the ioctl handler to make sure the op is being called for the right session type.

CVSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-68455

EUVD

EUVD-2026-59077

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves improper validation of session types before performing operations. The issue occurs when ioctl operations meant for one session type (e.g., incoming or outgoing) are incorrectly applied to another session type. This can lead to unexpected errors and internal kernel warnings.

Detection Guidance

This vulnerability is specific to the Linux kernel's liveupdate mechanism and requires kernel-level detection. No direct network or system commands are provided in the context to detect this issue. Monitoring kernel logs for WARN() messages from KHO related to session ioctl operations may indicate exploitation attempts.

Impact Analysis

This vulnerability could cause system instability or crashes if an attacker exploits it to trigger incorrect ioctl operations. It may also lead to unexpected behavior in applications relying on session management, potentially causing data corruption or denial of service.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It involves a Linux kernel issue where incorrect ioctl operations on session types could lead to unexpected errors or internal warnings, but no data exposure or privacy violation is described.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the liveupdate session validation issue. Monitor kernel logs for WARN() messages related to KHO_PAGE_MAGIC errors as potential indicators of exploitation attempts.

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