{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90071","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.784Z","datePublished":"2026-09-17T16:05:52.245Z","dateUpdated":"2026-09-18T17:52:54.125Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-18T17:52:54.125Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: restore skb->dev on the slave failure path\n\nteql_master_xmit() sets skb->dev = slave before calling the slave's\nndo_start_xmit(), but never restores it when that transmit fails. The\nskb then walks on to the next slave still pointing at the previous one.\n\nIf a later slave has no resolved neighbour, teql_resolve() hands the skb\nto neigh_event_send(), which queues it on that neighbour's arp_queue\nwith the stale skb->dev. skb->dev holds no reference, so deleting the\nprevious slave frees the net_device while the skb is still queued.\nWhatever runs next on that skb - arp_error_report() on timeout, or\nneigh_direct_output() -> dev_queue_xmit() once the neighbour resolves -\ncauses a UAF like the one below:\n\nBUG: KASAN: slab-use-after-free in __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\nRead of size 4 at addr ffff888106e100b0 by task flood_packet/527\nCPU: 0 UID: 0 PID: 527 Comm: flood_packet Not tainted 7.2.0-rc6-g594d90519502 #1 PREEMPT(lazy)\nHardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nCall Trace:\n<IRQ>\ndump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)\nprint_report (mm/kasan/report.c:378 mm/kasan/report.c:482)\n? __pfx__raw_spin_lock_irqsave (./include/asm-generic/qrwlock.h:122 (discriminator 4))\n? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\nkasan_report (mm/kasan/report.c:595)\n? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\n__icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\n[...]\nipv4_link_failure (net/ipv4/route.c:1251 net/ipv4/route.c:1258)\n? __pfx_ipv4_link_failure (./include/linux/skbuff.h:4327)\n? _raw_write_lock (./include/linux/instrumented.h:55 ./include/linux/atomic/atomic-instrumented.h:1301 ./include/asm-generic/qrwlock.h:98 ./include/linux/rwlock_api_smp.h:230 kernel/locking/spinlock.c:304)\n? __pfx__raw_write_lock (kernel/locking/spinlock.c:175)\narp_error_report (./include/net/dst.h:438 net/ipv4/arp.c:296)\nneigh_invalidate (net/core/neighbour.c:1077)\nneigh_timer_handler (net/core/neighbour.c:1169)\n[...]\nAllocated by task 505:\nkasan_save_stack (mm/kasan/common.c:57)\nkasan_save_track (mm/kasan/common.c:78)\n__kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)\n__kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5334 mm/slub.c:6905)\nalloc_netdev_mqs (net/core/dev.c:12055 (discriminator 2))\nrtnl_create_link (net/core/rtnetlink.c:3721)\nrtnl_newlink (net/core/rtnetlink.c:3903 net/core/rtnetlink.c:4044 net/core/rtnetlink.c:4159)\nrtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n[...]\nFreed by task 536:\nkasan_save_stack (mm/kasan/common.c:57)\nkasan_save_track (mm/kasan/common.c:78)\nkasan_save_free_info (mm/kasan/generic.c:584)\n__kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285)\nkfree (./include/linux/kasan.h:235 mm/slub.c:2677 mm/slub.c:6377 mm/slub.c:6692)\ndevice_release (drivers/base/core.c:2636)\nkobject_put (lib/kobject.c:689 lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737)\nnetdev_run_todo (net/core/dev.c:11756)\nrtnl_dellink (net/core/rtnetlink.c:157 ./include/linux/rtnetlink.h:135 net/core/rtnetlink.c:3651)\nrtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n[...]\n\nFix this by restoring skb->dev to the master at the end of each slave's\niteration."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - teql_master_xmit() itself writes skb->dev to the slave, and the UAF is completed by a local RTM_DELLINK (rtnl_dellink → netdev_run_todo) of that slave while the skb sits on another slave's arp_queue; the packet reaches teql_master_xmit via sendto/udp_sendmsg → ip_finish_output2 → __dev_queue_xmit on teql0, not via a remote protocol field.\nAC:L - The attacker chooses the slaves, sends on teql0 so teql_master_xmit() leaves skb->dev on a failed ndo_start_xmit/netif_xmit_frozen_or_stopped slave, then teql_resolve()/neigh_event_send() queues that skb for an unresolved neighbour, then issues RTM_DELLINK; flood_packet plus an unanswered ARP destination make this repeatable without third-party timing.\nPR:L - RTM_NEWLINK, RTM_NEWQDISC (tc_modify_qdisc → teql_qdisc_init) and the freeing RTM_DELLINK all go through rtnetlink_rcv_msg(), which requires netlink_net_capable(skb, CAP_NET_ADMIN) against sock_net(skb->sk)->user_ns; unshare -Urn grants that namespaced capability without init-namespace root.\nUI:N - The attacker alone creates the slaves, grafts the teql0 qdisc, injects packets into teql_master_xmit(), and deletes the stale skb->dev slave with RTM_DELLINK; no other user must open a file, mount a volume, or otherwise act.\nS:U - The freed object is a kernel net_device from alloc_netdev_mqs()/rtnl_newlink, used later on the same host via skb->dev in __icmp_send() or dev_queue_xmit(); this is in-kernel memory corruption, not a VM, IOMMU, or hypervisor boundary crossing.\nC:H - KASAN reports a slab-use-after-free read of the freed net_device in __icmp_send() (skb_in->dev->flags) from arp_error_report(); the same dangling skb->dev is consumed by neigh_direct_output() → dev_queue_xmit(), and reclaim of that slab object yields an arbitrary kernel read.\nI:H - Once the neighbour resolves, neigh_update_process_arp_queue() calls neigh_direct_output() → dev_queue_xmit() on the dangling skb->dev, so a reclaimed net_device's netdev_ops (ndo_start_xmit) become attacker-controlled, giving an arbitrary kernel write and control-flow hijack.\nA:H - The reported path is neigh_timer_handler() → neigh_invalidate() → arp_error_report() → ipv4_link_failure() → __icmp_send() hitting a KASAN slab-use-after-free of the deleted slave net_device, which oopses/panics the kernel even without further exploitation."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_teql.c"],"versions":[{"version":"383493b9940e3d1b5517424081b3e072e20ec43c","lessThan":"1360bc93f5be1be3cf937ebea667b3418dd30a79","status":"affected","versionType":"git"},{"version":"6b1f563d670162e188a0f2aec39c24b67b106e17","lessThan":"d453bf439ef230b5743afc25e194adacca8c6e43","status":"affected","versionType":"git"},{"version":"57c153249143333bbf4ecf927bdf8aa2696ee397","lessThan":"012559cf3c67ce8825a31d4f66b040b6fbaf775e","status":"affected","versionType":"git"},{"version":"59b06d8b9bdb6b64b3c534c18da68bce5ccd31be","lessThan":"aa39a790d56b40bfcf3861653ceb46a3a113adb6","status":"affected","versionType":"git"},{"version":"81a43e8005366f16e629d8c95dfe05beaa8d36a7","lessThan":"00d8a387b23b7831ad9919256a6b9caaa10f19c3","status":"affected","versionType":"git"},{"version":"0bad9c86edd22dec4df83c2b29872d66fd8a2ff4","lessThan":"96bc345a3f17543d0d92ada609e02198d6380e26","status":"affected","versionType":"git"},{"version":"0cc0c2e661af418bbf7074179ea5cfffc0a5c466","lessThan":"0cd75037948567193f7f5767176538822ce23873","status":"affected","versionType":"git"},{"version":"0cc0c2e661af418bbf7074179ea5cfffc0a5c466","lessThan":"dc4b95b8fee95113587e93ca116356032d271371","status":"affected","versionType":"git"},{"version":"21ea283c2750c8307aa35ee832b0951cc993c27d","status":"affected","versionType":"git"},{"version":"5.10.253","lessThan":"5.10.270","status":"affected","versionType":"semver"},{"version":"5.15.203","lessThan":"5.15.221","status":"affected","versionType":"semver"},{"version":"6.1.167","lessThan":"6.1.188","status":"affected","versionType":"semver"},{"version":"6.6.130","lessThan":"6.6.157","status":"affected","versionType":"semver"},{"version":"6.12.78","lessThan":"6.12.110","status":"affected","versionType":"semver"},{"version":"6.18.19","lessThan":"6.18.52","status":"affected","versionType":"semver"},{"version":"6.19.9","lessThan":"6.20","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/sch_teql.c"],"versions":[{"version":"7.0","status":"affected"},{"version":"0","lessThan":"7.0","status":"unaffected","versionType":"semver"},{"version":"5.10.270","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.221","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.110","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.52","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.6","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.253","versionEndExcluding":"5.10.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.203","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.167","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.130","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.78","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.19","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0","versionEndExcluding":"7.3-rc1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19.9"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/1360bc93f5be1be3cf937ebea667b3418dd30a79"},{"url":"https://git.kernel.org/stable/c/d453bf439ef230b5743afc25e194adacca8c6e43"},{"url":"https://git.kernel.org/stable/c/012559cf3c67ce8825a31d4f66b040b6fbaf775e"},{"url":"https://git.kernel.org/stable/c/aa39a790d56b40bfcf3861653ceb46a3a113adb6"},{"url":"https://git.kernel.org/stable/c/00d8a387b23b7831ad9919256a6b9caaa10f19c3"},{"url":"https://git.kernel.org/stable/c/96bc345a3f17543d0d92ada609e02198d6380e26"},{"url":"https://git.kernel.org/stable/c/0cd75037948567193f7f5767176538822ce23873"},{"url":"https://git.kernel.org/stable/c/dc4b95b8fee95113587e93ca116356032d271371"}],"title":"net/sched: sch_teql: restore skb->dev on the slave failure path","x_generator":{"engine":"bippy-1.2.0"}}}}