CVE-2026-80603

Technical Description

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

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

parse_dcc() treats data_end as an inclusive end pointer, but its only

caller passes data_limit = ib_ptr + 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 skb_header_pointer().

irc_buffer is kmalloc'd as MAX_SEARCH_SIZE + 1 bytes and datalen is

capped at MAX_SEARCH_SIZE, 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 exclusi

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References