{"id":"CVE-2026-90083","summary":"net/sched: act_ife: Only operate on Ethernet frames","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_ife: Only operate on Ethernet frames\n\nact_ife encapsulates/decapsulates the original Ethernet header and uses\nskb-\u003edev-\u003ehard_header_len as the length of that header. That is only\ncorrect for Ethernet devices: on a device where hard_header_len does not\nmatch the L2 header that was actually pulled (PPP reports PPP_HDRLEN\nwhile nothing is stripped on ingress), the ingress skb_push()/skb_pull()\nuse the wrong length and can hit skb_under_panic when headroom is tight.\n\nIFE is Ethernet-only by design - it builds an outer ethhdr, rewrites\nh_source/h_dest/h_proto, and calls eth_type_trans() on decode - so\ninstead of trying to make the offsets work for arbitrary link types,\nsimply drop packets that do not carry an Ethernet header.\n\nChecking skb-\u003edev-\u003etype alone is not enough. We have to cater for a\ncorner case where mirred can redirect an skb from a non-Ethernet device\nto an Ethernet one, and skb-\u003edev then says nothing about the framing the\nskb actually has: an skb redirected from ppp0 reaches the target's ingress\nhook with mac_len 0 and no Ethernet header at all. So at ingress also\nrequire mac_len to be ETH_HLEN. On egress mac_len is not maintained, so\nthe device type is all we have; a bogus redirect there yields a malformed\nframe rather than an out-of-bounds push, and it would be malformed with or\nwithout IFE.\n\nThat corner case is not theoretical - redirecting from ppp0 into a veth\nthat has an ife encode action on its ingress hook panics without this\npatch:\n\n  skbuff: skb_under_panic: len:98 put:14 head:ffff88800e410000\n          data:ffff88800e40fff5 tail:0x57 end:0x640 dev:veth3\n  kernel BUG at net/core/skbuff.c:214!\n  Call Trace:\n   skb_push (net/core/skbuff.c:224 net/core/skbuff.c:2657)\n   tcf_ife_act (net/sched/act_ife.c:829 net/sched/act_ife.c:874)\n   tc_run (net/core/dev.c:4463)\n   netif_receive_skb (net/core/dev.c:6463 net/core/dev.c:6522)\n   tcf_mirred_to_dev (net/sched/act_mirred.c:248 net/sched/act_mirred.c:328)\n   tcf_mirred_act (net/sched/act_mirred.c:489)\n   tc_run (net/core/dev.c:4463)\n   process_backlog (net/core/dev.c:6728)\n\nWith Ethernet framing guaranteed, use ETH_HLEN instead of\nhard_header_len.","modified":"2026-09-19T03:47:31.016732519Z","published":"2026-09-17T16:06:00.185Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90083.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/138b0054021fd7d57bc3eb68b3f4e2bcec037849"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5b483f7791b079bb97d411f1066652ff659207ff"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d218ea7df6eba076171f2d4897a429a31f2139f0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90083.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90083"},{"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":"295a6e06d21e1f469c9f38b00125a13b60ad4e7c"},{"fixed":"d218ea7df6eba076171f2d4897a429a31f2139f0"},{"fixed":"138b0054021fd7d57bc3eb68b3f4e2bcec037849"},{"fixed":"5b483f7791b079bb97d411f1066652ff659207ff"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90083.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.11.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90083.json"}}],"schema_version":"1.9.0"}