Paper/Archive/CVE-2026-80603

CVE-2026-80603

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

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7eabb8c32b88ea3f46beb68c34fe9a3ac8ed664e7eCNA
Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 437e0a3854b3a44ec15afa9ab88ec215adf3a2fd437e0a3854b3a44ec15afa9ab88ec215adf3a2fdCNA
Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1CNA
Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 2b70f61f569bb29acb380e6f616a1bbdee15668f2b70f61f569bb29acb380e6f616a1bbdee15668fCNA
Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 2393f0bd7a467ad475598f3a5b9de27ca36e30372393f0bd7a467ad475598f3a5b9de27ca36e3037CNA
Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < aff589556ed772cb1c0c2d7b4d91ec45c0c39416aff589556ed772cb1c0c2d7b4d91ec45c0c39416CNA
Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < eeef3b81f449560653662df2dde6f6fe247c5365eeef3b81f449560653662df2dde6f6fe247c5365CNA
Linux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88aef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88aCNA
Linux2.6.12–CNA

Scores by source

Linux (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgit.kernel.org/stable/c/abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7erefgit.kernel.org/stable/c/437e0a3854b3a44ec15afa9ab88ec215adf3a2fdrefgit.kernel.org/stable/c/910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1refgit.kernel.org/stable/c/2b70f61f569bb29acb380e6f616a1bbdee15668frefgit.kernel.org/stable/c/2393f0bd7a467ad475598f3a5b9de27ca36e3037refgit.kernel.org/stable/c/aff589556ed772cb1c0c2d7b4d91ec45c0c39416refgit.kernel.org/stable/c/eeef3b81f449560653662df2dde6f6fe247c5365refgit.kernel.org/stable/c/ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a