# CVE-2026-97957: net: hinic: fix mailbox segment buffer overflow

> A heap buffer overflow in the Linux kernel hinic network driver allows attackers to potentially execute code or cause a system crash.

- **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104207, BELL-CVE-2026-97957, DEBIAN-CVE-2026-97957, GHSA-f67x-rg3m-rrxf, UBUNTU-CVE-2026-97957

## What is CVE-2026-97957?

CVE-2026-97957 is a high-severity memory corruption 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: hinic: fix mailbox segment buffer overflow

check_mbox_seq_id_and_seg_len() validates that seq_id does not
exceed SEQ_ID_MAX_VAL (42) and seg_len does not exceed
MBOX_SEG_LEN (48).  However, this allows the last segment
(seq_id=42) to carry a full 48-byte payload, writing to offset
42*48=2016 for 48 bytes (ending at byte 2064).  The receive
buffer is only MBOX_MAX_BUF_SZ (2048) bytes, resulting in a
16-byte heap buffer overflow.

The hinic3 driver already handles this correctly by defining
MBOX_LAST_SEG_MAX_LEN and rejecting the last segment when it
exceeds the remaining buffer space.  Apply the same fix to the
hinic driver.

## Which versions are affected by CVE-2026-97957?


## How do I fix CVE-2026-97957?

Apply the vendor's patch.

## Is CVE-2026-97957 being exploited?

There is no known exploitation of CVE-2026-97957 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97957 and fix it if it is affected.

What it is: CVE-2026-97957 is a high-severity memory corruption 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-2026-97957 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-2026-97957/ (Markdown: https://insights.sbomify.com/CVE-2026-97957/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97957
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97957
- OSV: https://osv.dev/vulnerability/CVE-2026-97957

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97957/
Summaries are generated and may contain mistakes; the official description above is the record.