---
id: "CVE-2026-98576"
kind: "vulnerability"
aliases: ["CVE-2026-98576"]
title: "Linux kernel NFC LLCP: debug logging reads past service name buffers"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["linux-kernel", "nfc", "runtime", "self-hosted"]
not_affected_if: ["nfc-module-not-loaded", "no-nfc-hardware"]
published_at: "2026-10-18T16:17:09+00:00"
first_seen_at: "2026-10-23T21:57:15+00:00"
updated_at: "2026-10-25T05:23:08+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98576", "first_seen_at": "2026-10-23T21:57:15+00:00"}]
---

# Linux kernel NFC LLCP: debug logging reads past service name buffers

The Linux kernel NFC LLCP code passes service name strings that are not null-terminated to a debug print routine, so logging can read past the end of the allocated buffer. The sources describe an out-of-bounds read detected by KASAN, not a confirmed code execution or data-disclosure path.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `uname -r` and check whether the kernel build includes the NFC LLCP fix (the source commit uses %.*s in nfc_llcp_wks_sap and nfc_llcp_build_sdreq_tlv)
- Check whether the `nfc` module is loaded with `lsmod | grep nfc`

## Fix

- Update the Linux kernel to a release that includes the upstream nfc: llcp fix (version unknown from the sources)

## Timeline

- 2026-10-23T21:57:15+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98576

## From the sources

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

nfc: llcp: fix slab-out-of-bounds reads when logging service names

nfc_llcp_wks_sap() and nfc_llcp_build_sdreq_tlv() pass non-null-
terminated strings to pr_debug() using the %s format specifier.
The buffers are allocated via kmemdup() or come from netlink
attributes and are not guaranteed to be null-terminated, causing
__dynamic_pr_debug() to read beyond the allocated region:

  KASAN: slab-out-of-bounds Read in __dynamic_pr_debug

Fix both call sites by using %.*s with the explicit length to limit
the output to the actual length of the string.

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