{"id":"CVE-2026-74476","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74476","summary":"veth: convert frag_list skbs before running XDP","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nveth: convert frag_list skbs before running XDP\n\nA frag_list skb can reach veth with data_len set but nr_frags zero.\nveth_convert_skb_to_xdp_buff() only converts skbs that are shared,\nlocked, have frags[], or do not have enough headroom. It later uses\nskb_is_nonlinear() to decide whether to set XDP_FLAGS_HAS_FRAGS and\nxdp_frags_size.\n\nThat exposes frag_list data to XDP as if it were stored in frags[], but\nfrags[] is empty. AF_XDP copy mode can then trust the bogus XDP fragment\nmetadata, walk an empty fragment entry, and crash in memcpy() from\n__xsk_rcv().\n\nRoute non-linear skbs through skb_pp_cow_data() before exposing them to\nXDP, and only advertise XDP frags when the resulting skb has frags[].\nskb_copy_bits() already handles frag_list input, and skb_pp_cow_data()\nbuilds frags[] output with skb_add_rx_frag(), which is the\nrepresentation XDP multi-buffer expects.","published":"2026-08-15T12:27:11.309Z","modified":"2026-08-18T03:56:57.960695906Z","cvss":{"score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.12.103"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5c1c15c540fc45820ce3033c319151ec891bc10a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b24ba0bbffe3e23eb2f6838881c1fabcb29fb9fb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d0d6415963040c401e7a7e4e482a698ba52448cb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f9c1fff857e93be709c8b52ed1a643f37bd82c66"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74476.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74476"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:57.960695906Z"}}