CVE-2026-80603

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

netfilter: nfconntrackirc: fix parse_dcc() off-by-one OOB read

parsedcc() treats dataend as an inclusive end pointer, but its only

caller passes datalimit = ibptr + datalen, which points one past the

last valid byte.

The newline search loop iterates while tmp <= data_end, so when no

newline is present, *tmp is read at tmp == data_end, one byte beyond

the region filled by skbheaderpointer().

ircbuffer is kmalloc'd as MAXSEARCH_SIZE + 1 bytes and datalen is

capped at MAXSEARCHSIZE, so the stray read does not fault.  The byte

is uninitialized or stale; if it contains an ASCII digit, simple_strtoul

will consume it and produce a wrong DCC IP or port in the conntrack

expectation.  The extra allocation byte is also a fragile guard: if the

cap or allocation size changes, this becomes a real out-of-bounds read.

Change the loop and its post-loop check to use strict less-than,

consistent with the caller's exclusive-end convention.  Update the

function comment accordingly.