CVE-2026-98577: nfc: llcp: fix WKS SAP hijacking via prefix match in nfc_llcp_wks_sap()

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-18 · updated 2026-10-19

Description

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().

Affected products

Linux kernel: 3.3 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/0a0412745c86acd089c6460da715ab966b1615e7
https://git.kernel.org/stable/c/0c83a8a45fed256ccc5fe7160b436b671fc79fb8
https://git.kernel.org/stable/c/32b5f0b338bf59391a1cff9a6190a72c4d2c1ba8
https://git.kernel.org/stable/c/408cff6bd60636df201274d320edfdfde9ed41db
https://git.kernel.org/stable/c/6fad2c34d451d11a9f3f946cae1105fee91d96b8
https://git.kernel.org/stable/c/aa555ed5ed0d15efbaf27e0e9f152a6df715278a
https://git.kernel.org/stable/c/bf41af8f910cbb5d776a1dfa0671d31a7e262e28
https://git.kernel.org/stable/c/f234197f3bda3aea5d4b1e591d6bcb3660a8b3fc

Get alerted when CVE-2026-98577 or the next vulnerability affects your stack