# CVE-2026-98725: nvmet-auth: fix out-of-bounds write in nvmet_auth_challenge()

> An out-of-bounds write in the Linux kernel NVMe target authentication allows remote attackers to cause a denial of service or potentially execute code.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-109118, BELL-CVE-2026-98725, DEBIAN-CVE-2026-98725, GHSA-h488-w8xm-x8gw, UBUNTU-CVE-2026-98725

## What is CVE-2026-98725?

CVE-2026-98725 is a memory corruption vulnerability in Linux, published on 18 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

nvmet-auth: fix out-of-bounds write in nvmet_auth_challenge()

nvmet_auth_challenge() receives its output buffer as a void pointer.
sizeof(*d) therefore evaluates to one with GCC and undercounts the fixed
challenge header by 15 bytes.  A short AUTH_RECEIVE buffer can pass the
check before the challenge is copied past the end of its allocation.

Use the typed challenge pointer when calculating the response size.

  BUG: KASAN: slab-out-of-bounds in nvmet_execute_auth_receive (drivers/nvme/target/fabrics-cmd-auth.c:442 drivers/nvme/target/fabrics-cmd-auth.c:569)
  Write of size 32 by task kworker/1:1H/64
  Workqueue: nvmet_tcp_wq nvmet_tcp_io_work
  Call Trace:
  nvmet_execute_auth_receive (drivers/nvme/target/fabrics-cmd-auth.c:442 drivers/nvme/target/fabrics-cmd-auth.c:569)
  nvmet_tcp_try_recv_pdu (drivers/nvme/target/tcp.c:1119 drivers/nvme/target/tcp.c:1243)
  nvmet_tcp_io_work (drivers/nvme/target/tcp.c:1350 drivers/nvme/target/tcp.c:1382 drivers/nvme/target/tcp.c:1445)
  process_one_work (kernel/workqueue.c:3322)
  worker_thread (kernel/workqueue.c:3405 kernel/workqueue.c:3486)
  kthread (kernel/kthread.c:436)
  ret_from_fork (arch/x86/kernel/process.c:158)
  ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
  The buggy address is located 16 bytes inside of
   allocated 33-byte region [ffff888000554e80, ffff888000554ea1)
  Kernel panic - not syncing: KASAN: panic_on_warn set ...

## Which versions are affected by CVE-2026-98725?


## How do I fix CVE-2026-98725?

Apply the vendor's patch.

## Is CVE-2026-98725 being exploited?

There is no known exploitation of CVE-2026-98725 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98725 and fix it if it is affected.

What it is: CVE-2026-98725 is a memory corruption vulnerability in Linux, published on 18 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98725 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-2026-98725/ (Markdown: https://insights.sbomify.com/CVE-2026-98725/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98725
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98725
- OSV: https://osv.dev/vulnerability/CVE-2026-98725

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98725/
Summaries are generated and may contain mistakes; the official description above is the record.