published September 4, 2026
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.