{"id":"AZL-101894","summary":"CVE-2026-90071 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: restore skb-\u003edev on the slave failure path\n\nteql_master_xmit() sets skb-\u003edev = 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-\u003edev. skb-\u003edev 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() -\u003e 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\u003cIRQ\u003e\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-\u003edev to the master at the end of each slave's\niteration.","modified":"2026-09-19T05:33:49Z","published":"2026-09-17T17:16:56Z","upstream":["CVE-2026-90071"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90071"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-101894.json"}}],"schema_version":"1.9.0"}