# CVE-2025-68795: ethtool: Avoid overflowing userspace buffer on stats query

> A buffer overflow in the Linux kernel ethtool stats query allows local attackers to potentially execute code or escalate privileges.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 13 Jan 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-74411, BELL-CVE-2025-68795, DEBIAN-CVE-2025-68795, GHSA-fv49-mrx3-2jvj, ROOT-OS-UBUNTU-2204-CVE-2025-68795, ROOT-OS-UBUNTU-2404-CVE-2025-68795, UBUNTU-CVE-2025-68795

## What is CVE-2025-68795?

CVE-2025-68795 is a high-severity memory corruption vulnerability in Linux, published on 13 Jan 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:

ethtool: Avoid overflowing userspace buffer on stats query

The ethtool -S command operates across three ioctl calls:
ETHTOOL_GSSET_INFO for the size, ETHTOOL_GSTRINGS for the names, and
ETHTOOL_GSTATS for the values.

If the number of stats changes between these calls (e.g., due to device
reconfiguration), userspace's buffer allocation will be incorrect,
potentially leading to buffer overflow.

Drivers are generally expected to maintain stable stat counts, but some
drivers (e.g., mlx5, bnx2x, bna, ksz884x) use dynamic counters, making
this scenario possible.

Some drivers try to handle this internally:
- bnad_get_ethtool_stats() returns early in case stats.n_stats is not
  equal to the driver's stats count.
- micrel/ksz884x also makes sure not to write anything beyond
  stats.n_stats and overflow the buffer.

However, both use stats.n_stats which is already assigned with the value
returned from get_sset_count(), hence won't solve the issue described
here.

Change ethtool_get_strings(), ethtool_get_stats(),
ethtool_get_phy_stats() to not return anything in case of a mismatch
between userspace's size and get_sset_size(), to prevent buffer
overflow.
The returned n_stats value will be equal to zero, to reflect that
nothing has been returned.

This could result in one of two cases when using upstream ethtool,
depending on when the size change is detected:
1. When detected in ethtool_get_strings():
    # ethtool -S eth2
    no stats available

2. When detected in get stats, all stats will be reported as zero.

Both cases are presumably transient, and a subsequent ethtool call
should succeed.

Other than the overflow avoidance, these two cases are very evident (no
output/cleared stats), which is arguably better than presenting
incorrect/shifted stats.
I also considered returning an error instead of a "silent" response, but
that seems more destructive towards userspace apps.

Notes:
- This patch does not claim to fix the inherent race, it only makes sure
  that we do not overflow the userspace buffer, and makes for a more
  predictable behavior.

- RTNL lock is held during each ioctl, the race window exists between
  the separate ioctl calls when the lock is released.

- Userspace ethtool always fills stats.n_stats, but it is likely that
  these stats ioctls are implemented in other userspace applications
  which might not fill it. The added code checks that it's not zero,
  to prevent any regressions.

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2025-68795?


## How do I fix CVE-2025-68795?

Apply the vendor's patch.

## Is CVE-2025-68795 being exploited?

There is no known exploitation of CVE-2025-68795 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68795 and fix it if it is affected.

What it is: CVE-2025-68795 is a high-severity memory corruption vulnerability in Linux, published on 13 Jan 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-2025-68795 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-2025-68795/ (Markdown: https://insights.sbomify.com/CVE-2025-68795/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68795
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68795
- OSV: https://osv.dev/vulnerability/CVE-2025-68795

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68795/
Summaries are generated and may contain mistakes; the official description above is the record.