# CVE-2026-98807: net/mlx5: Fix slab-out-of-bounds when handling team device events

> A slab-out-of-bounds memory access in the Linux kernel mlx5 driver allows local attackers to cause a denial of service via team device events.

- **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:** 19 Oct 2026
- **Also known as:** AZL-108909, BELL-CVE-2026-98807, DEBIAN-CVE-2026-98807, GHSA-7rpx-hg5j-v22f, UBUNTU-CVE-2026-98807

## What is CVE-2026-98807?

CVE-2026-98807 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:

net/mlx5: Fix slab-out-of-bounds when handling team device events

The mlx5_handle_changeupper_event() and mlx5_handle_changeinfodata_event()
functions check for LAG masters (which includes both bonding and team
devices) but only call bonding-specific APIs. When processing team device
events, calling bond_slave_get_rcu() and bond_is_slave_inactive() on
team_port structures causes KASAN to detect an out-of-bounds memory access
since team_port is smaller than bond slave.

Fix this by wrapping the bond-specific API calls with a check for bonding
devices. This allows the function to still process LAG events for both
bonding and teams but only calls bond-specific functions when dealing with
actual bonding devices.

For mlx5_handle_changeinfodata_event(), keep the explicit bond check as
mlx5 doesn't handle state information for team ports anyway.

Tested with Mellanox ConnectX-5 on Linux 7.2.0-rc6:
- Bonding: PASS (no regressions)
- Team device: PASS (no KASAN errors)

## Which versions are affected by CVE-2026-98807?


## How do I fix CVE-2026-98807?

Apply the vendor's patch.

## Is CVE-2026-98807 being exploited?

There is no known exploitation of CVE-2026-98807 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98807 and fix it if it is affected.

What it is: CVE-2026-98807 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-2026-98807 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-2026-98807/ (Markdown: https://insights.sbomify.com/CVE-2026-98807/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98807
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98807
- OSV: https://osv.dev/vulnerability/CVE-2026-98807

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98807/
Summaries are generated and may contain mistakes; the official description above is the record.