CVE-2026-80799 — nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers

Affected: Linux

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

nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers

nfc_llcp_parse_gb_tlv() and nfc_llcp_parse_connection_tlv() contain three related bugs in their TLV parsing loops:

1. 'offset' is declared u8 but tlv_array_len is u16. When TLV data advances offset past 255 it silently wraps to zero, causing infinite loops or double-processing of buffer data.

2. Before reading tlv[0] (type) and tlv[1] (length) there is no check that offset+2 <= tlv_array_len. A truncated TLV causes an OOB read of one byte past the buffer end.

3. After reading the length field, the value bytes are accessed without checking offset+2+length <= tlv_array_len. A crafted length=0xFF on a short buffer causes up to 255 bytes of OOB read past the buffer end.

Both functions are reachable without authentication via nfc_llcp_set_remote_gb() which feeds remote LLCP general bytes directly into nfc_llcp_parse_gb_tlv() with no additional validation.

Fix all three issues by widening offset from u8 to u16 and adding bounds checks for both the TLV header and value field before each access.

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CVE-2026-80799 — nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers