# CVE-2026-98015: net/mlx5: E-Switch: fix use-after-free in mlx5_eswitch_termtbl_put

> A use-after-free in the Linux kernel mlx5 E-Switch driver allows local attackers to execute arbitrary code or escalate privileges via race conditions.

- **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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104298, BELL-CVE-2026-98015, DEBIAN-CVE-2026-98015, GHSA-wg7p-rcj6-hf3p, UBUNTU-CVE-2026-98015

## What is CVE-2026-98015?

CVE-2026-98015 is an use after free vulnerability in Linux, published on 25 Sep 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:

net/mlx5: E-Switch: fix use-after-free in mlx5_eswitch_termtbl_put

In mlx5_eswitch_termtbl_put(), the zero-ref cleanup check reads
tt->ref_count after termtbl_mutex has been released.  Two concurrent
callers on the same mlx5_termtbl_handle race: one decrements ref_count
to zero, removes the hash entry, and calls kfree(tt) while the other
has already dropped the mutex and is about to evaluate
if (!tt->ref_count), producing a use-after-free.

Fix this by capturing the result of the decrement into a stack-local
last variable before dropping the mutex.  The cleanup decision is now
made entirely under termtbl_mutex, and tt is not touched after
kfree.

## Which versions are affected by CVE-2026-98015?


## How do I fix CVE-2026-98015?

Apply the vendor's patch.

## Is CVE-2026-98015 being exploited?

There is no known exploitation of CVE-2026-98015 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98015 and fix it if it is affected.

What it is: CVE-2026-98015 is an use after free vulnerability in Linux, published on 25 Sep 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-2026-98015 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-2026-98015/ (Markdown: https://insights.sbomify.com/CVE-2026-98015/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98015
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98015
- OSV: https://osv.dev/vulnerability/CVE-2026-98015

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98015/
Summaries are generated and may contain mistakes; the official description above is the record.