# CVE-2026-68090: debugobjects: Plug race against a concurrent OOM disable

> A race condition in the Linux kernel debugobjects subsystem can cause a timer malfunction and system warning when debug objects are disabled due to out-of-memory conditions.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-68090, DEBIAN-CVE-2026-68090, GHSA-qrrw-365j-cfxh, UBUNTU-CVE-2026-68090

## What is CVE-2026-68090?

CVE-2026-68090 is a vulnerability in Linux, published on 10 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:

debugobjects: Plug race against a concurrent OOM disable

syzbot reported a puzzling splat:

   WARNING: kernel/time/hrtimer.c:443 at stub_timer+0xa/0x20

stub_timer() is installed as timer callback function in
hrtimer_fixup_assert_init(), which is invoked when
debug_object_assert_init() can't find a shadow object. In that case debug
objects emits a warning about it before invoking the fixup.

Though the provided console log lacks this warning and instead has the
following a few seconds before the splat:

     ODEBUG: Out of memory. ODEBUG disabled

So the object was looked up in debug_object_assert_init() and the lookup
failed due a concurrent out of memory situation which disabled debug
objects and freed the shadow objects:

debug_object_assert_init()
        if (!debug_objects_enabled)
        	return;                         obj = alloc();
                				if (!obj) {
							// Out of memory
                                                	debug_objects_enabled = false;
                                                        free_objects();
        obj = lookup_or_alloc();

        // The lookup failed because the other side
        // removed the objects, so this returns
        // an error code as the object in question
        // is not statically initialized

	if (!IS_ERR_OR_NULL(obj))
        	return;
        if (!obj) {
        	debug_oom();
                return;
        }

        print(...)
           if (!debug_objects_enabled)
                return;

        fixup(...)

The debug object splat is skipped because debug_objects_enabled is false,
but the fixup callback is invoked unconditionally, which makes the timer
disfunctional.

This is only a problem in debug_object_assert_init() and
debug_object_activate() as both have to handle statically initialized
objects and therefore must handle the error pointer return case
gracefully. All other places only handle the found/not found case and the
NULL pointer return is a signal for OOM. Otherwise they get a valid shadow
object.

Plug the hole by checking whether debug objects are still enabled before
invoking the print and fixup function in those two places.

## Which versions are affected by CVE-2026-68090?


## How do I fix CVE-2026-68090?

Apply the vendor's patch.

## Is CVE-2026-68090 being exploited?

There is no known exploitation of CVE-2026-68090 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68090 and fix it if it is affected.

What it is: CVE-2026-68090 is a vulnerability in Linux, published on 10 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-2026-68090 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-2026-68090/ (Markdown: https://insights.sbomify.com/CVE-2026-68090/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68090
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68090
- OSV: https://osv.dev/vulnerability/CVE-2026-68090

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68090/
Summaries are generated and may contain mistakes; the official description above is the record.