{"id":"CVE-2026-80603","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-80603","summary":"netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read\n\nparse_dcc() treats data_end as an inclusive end pointer, but its only\ncaller passes data_limit = ib_ptr + datalen, which points one past the\nlast valid byte.\n\nThe newline search loop iterates while tmp <= data_end, so when no\nnewline is present, *tmp is read at tmp == data_end, one byte beyond\nthe region filled by skb_header_pointer().\n\nirc_buffer is kmalloc'd as MAX_SEARCH_SIZE + 1 bytes and datalen is\ncapped at MAX_SEARCH_SIZE, so the stray read does not fault.  The byte\nis uninitialized or stale; if it contains an ASCII digit, simple_strtoul\nwill consume it and produce a wrong DCC IP or port in the conntrack\nexpectation.  The extra allocation byte is also a fragile guard: if the\ncap or allocation size changes, this becomes a real out-of-bounds read.\n\nChange the loop and its post-loop check to use strict less-than,\nconsistent with the caller's exclusive-end convention.  Update the\nfunction comment accordingly.","published":"2026-08-28T06:48:29.158Z","modified":"2026-08-30T03:48:23.078309004Z","cvss":{"score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.10.261"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2393f0bd7a467ad475598f3a5b9de27ca36e3037"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2b70f61f569bb29acb380e6f616a1bbdee15668f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/437e0a3854b3a44ec15afa9ab88ec215adf3a2fd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/910c33e4a8c046c3cc1fa5a465a4d41a1bb398f1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/abb8c32b88ea3f46beb68c34fe9a3ac8ed664e7e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/aff589556ed772cb1c0c2d7b4d91ec45c0c39416"},{"type":"WEB","url":"https://git.kernel.org/stable/c/eeef3b81f449560653662df2dde6f6fe247c5365"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ef6400ca25a13fd6dedbe8ef4a1d0979bbbfe88a"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80603.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80603"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-30T03:48:23.078309004Z"}}