# CVE-2026-22998: nvme-tcp: fix NULL pointer dereferences in nvmet_tcp_build_pdu_iovec

> A remote attacker can cause a kernel crash by sending malformed NVMe-TCP PDUs before proper initialization, affecting Linux systems using NVMe over TCP.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Jan 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-78482, AZL-78491, BELL-CVE-2026-22998, DEBIAN-CVE-2026-22998, GHSA-xjx5-8v38-q6gh, ROOT-OS-DEBIAN-11-CVE-2026-22998, ROOT-OS-DEBIAN-12-CVE-2026-22998, ROOT-OS-DEBIAN-13-CVE-2026-22998, ROOT-OS-UBUNTU-2204-CVE-2026-22998, ROOT-OS-UBUNTU-2404-CVE-2026-22998, UBUNTU-CVE-2026-22998

## What is CVE-2026-22998?

CVE-2026-22998 is a high-severity vulnerability in Linux kernel, published on 25 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

nvme-tcp: fix NULL pointer dereferences in nvmet_tcp_build_pdu_iovec

Commit efa56305908b ("nvmet-tcp: Fix a kernel panic when host sends an invalid H2C PDU length")
added ttag bounds checking and data_offset
validation in nvmet_tcp_handle_h2c_data_pdu(), but it did not validate
whether the command's data structures (cmd->req.sg and cmd->iov) have
been properly initialized before processing H2C_DATA PDUs.

The nvmet_tcp_build_pdu_iovec() function dereferences these pointers
without NULL checks. This can be triggered by sending H2C_DATA PDU
immediately after the ICREQ/ICRESP handshake, before
sending a CONNECT command or NVMe write command.

Attack vectors that trigger NULL pointer dereferences:
1. H2C_DATA PDU sent before CONNECT → both pointers NULL
2. H2C_DATA PDU for READ command → cmd->req.sg allocated, cmd->iov NULL
3. H2C_DATA PDU for uninitialized command slot → both pointers NULL

The fix validates both cmd->req.sg and cmd->iov before calling
nvmet_tcp_build_pdu_iovec(). Both checks are required because:
- Uninitialized commands: both NULL
- READ commands: cmd->req.sg allocated, cmd->iov NULL
- WRITE commands: both allocated

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-22998?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-22998?

Apply the vendor's patch.

## Is CVE-2026-22998 being exploited?

There is no known exploitation of CVE-2026-22998 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22998 and fix it if it is affected.

What it is: CVE-2026-22998 is a high-severity vulnerability in Linux kernel, published on 25 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-22998 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-22998/ (Markdown: https://insights.sbomify.com/CVE-2026-22998/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22998
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22998
- OSV: https://osv.dev/vulnerability/CVE-2026-22998

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22998/
Summaries are generated and may contain mistakes; the official description above is the record.