# CVE-2026-98831: of/overlay: don't leak fragment references when changeset init fails

> A memory leak in the Linux kernel's overlay changeset initialization can lead to resource exhaustion and denial of service.

- **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:** 18 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-109218, BELL-CVE-2026-98831, DEBIAN-CVE-2026-98831, GHSA-vvrp-cfq6-9c5c, UBUNTU-CVE-2026-98831

## What is CVE-2026-98831?

CVE-2026-98831 is a memory corruption vulnerability in Linux, published on 18 Oct 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:

of/overlay: don't leak fragment references when changeset init fails

init_overlay_changeset() stores the number of initialized fragments
in ovcs->count only on full success. When find_target() or the
__symbols__ lookup fails partway through, the target and overlay
references taken for the fragments initialized so far are never
dropped: free_overlay_changeset() bounds its cleanup loop by
ovcs->count, which is still 0.

Store the running count on the error path so free_overlay_changeset()
puts whatever was set up. The store is guarded by ovcs->fragments
because on the allocation-failure path cnt still holds the counting
pass total while there is no fragments array; everywhere else cnt
only counts fully-initialized fragments.

## Which versions are affected by CVE-2026-98831?


## How do I fix CVE-2026-98831?

Apply the vendor's patch.

## Is CVE-2026-98831 being exploited?

There is no known exploitation of CVE-2026-98831 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98831 and fix it if it is affected.

What it is: CVE-2026-98831 is a memory corruption vulnerability in Linux, published on 18 Oct 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-2026-98831 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-2026-98831/ (Markdown: https://insights.sbomify.com/CVE-2026-98831/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98831
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98831
- OSV: https://osv.dev/vulnerability/CVE-2026-98831

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98831/
Summaries are generated and may contain mistakes; the official description above is the record.