# CVE-2026-68455: liveupdate: validate session type before performing operation

> A local attacker can trigger kernel warnings and potential instability by invoking invalid ioctls on liveupdate sessions, requiring a kernel patch.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-68455, GHSA-97h6-xqf8-jhvx, UBUNTU-CVE-2026-68455

## What is CVE-2026-68455?

CVE-2026-68455 is a denial of service vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

## Which versions are affected by CVE-2026-68455?


## How do I fix CVE-2026-68455?

Apply the vendor's patch.

## Is CVE-2026-68455 being exploited?

There is no known exploitation of CVE-2026-68455 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68455 and fix it if it is affected.

What it is: CVE-2026-68455 is a denial of service vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68455 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68455/ (Markdown: https://insights.sbomify.com/CVE-2026-68455/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68455
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68455
- OSV: https://osv.dev/vulnerability/CVE-2026-68455

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68455/
Summaries are generated and may contain mistakes; the official description above is the record.