Bug 2525369 (CVE-2026-80603) - CVE-2026-80603 kernel: netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read
Summary: CVE-2026-80603 kernel: netfilter: nf_conntrack_irc: fix parse_dcc() off-by-on...
Keywords:
Status: NEW
Alias: CVE-2026-80603
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-28 07:41 UTC by OSIDB Bzimport
Modified: 2026-09-03 15:36 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-08-28 07:41:27 UTC
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 exclusive-end convention.  Update the
function comment accordingly.


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