---
id: "CVE-2026-98577"
kind: "vulnerability"
aliases: ["CVE-2026-98577"]
title: "Linux kernel NFC LLCP: short service name hijacks well-known SAP"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["embedded", "infrastructure", "linux-kernel", "nfc"]
not_affected_if: ["nfc-module-not-loaded", "no-nfc-hardware"]
published_at: "2026-10-18T16:17:10+00:00"
first_seen_at: "2026-10-23T21:57:15+00:00"
updated_at: "2026-10-25T05:23:05+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98577", "first_seen_at": "2026-10-23T21:57:15+00:00"}]
---

# Linux kernel NFC LLCP: short service name hijacks well-known SAP

The Linux kernel NFC LLCP code matches service names by prefix, so a short service name such as "u" is treated as a longer well-known service like "urn:nfc:sn:snep". An attacker on a near-field link can likely redirect traffic meant for a standard NFC service to their own service.

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

## How to check

- unknown

## Fix

- Install a Linux kernel release that includes the upstream fix for nfc_llcp_wks_sap() which requires an exact length match before strncmp().

## Timeline

- 2026-10-23T21:57:15+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98577

## From the sources

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

nfc: llcp: fix WKS SAP hijacking via prefix match in nfc_llcp_wks_sap()

nfc_llcp_wks_sap() compares only service_name_len bytes, so a short
service_name like "u" matches longer WKS strings like "urn:nfc:sn:snep".
Fix by requiring exact length match before strncmp().

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_