{"id":"CVE-2026-74668","summary":"packet: use consistent hard_header_len in TX_RING send path","details":"In the Linux kernel, the following vulnerability has been resolved:\n\npacket: use consistent hard_header_len in TX_RING send path\n\ntpacket_snd() reads dev-\u003ehard_header_len independently for skb\nallocation and header construction in tpacket_fill_skb(). Concurrent\nnetdevice reconfiguration can therefore make the reserved headroom\nsmaller than the amount later pushed, or make copylen - hard_header_len\nnegative.\n\nSnapshot hard_header_len once before processing ring frames and use it\nfor the frame limit, headroom allocation, copy length, and skb\nconstruction. Pass the snapshot to tpacket_fill_skb().\n\nThe separate SOCK_DGRAM consistency problem between hard_header_len and\nheader_ops-\u003ecreate is not addressed here.","modified":"2026-08-28T11:30:46.658151520Z","published":"2026-08-22T15:32:39.583Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74668.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/016763e829cac37b3234eace86fd0a4c560de4a7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/21b5953e7494c16a42e6cd8cf110e18d13ae4a6b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/27e068d1b35dbec10a3cf268887c94407be4badc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2a73b2c37ee3060a880b53cd24783d93fc7be5f8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9c7e8ff48c377bef18c3d178748aea0575b69ede"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d48ea5c9c4c34dc0df621f0e39ed3a16b644621a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d85d2fd54e901637c81d847811e03c662aee13cd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74668.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74668"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1"},{"fixed":"9c7e8ff48c377bef18c3d178748aea0575b69ede"},{"fixed":"2a73b2c37ee3060a880b53cd24783d93fc7be5f8"},{"fixed":"e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2"},{"fixed":"d85d2fd54e901637c81d847811e03c662aee13cd"},{"fixed":"016763e829cac37b3234eace86fd0a4c560de4a7"},{"fixed":"27e068d1b35dbec10a3cf268887c94407be4badc"},{"fixed":"d48ea5c9c4c34dc0df621f0e39ed3a16b644621a"},{"fixed":"21b5953e7494c16a42e6cd8cf110e18d13ae4a6b"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-74668.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.31"},{"fixed":"5.10.267"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.218"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.185"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.152"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.104"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.45"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-74668.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}