Bug 2541177 (CVE-2026-97595) - CVE-2026-97595 kernel: mac802154: fix use-after-free of sdata via queued RX frames
Summary: CVE-2026-97595 kernel: mac802154: fix use-after-free of sdata via queued RX f...
Keywords:
Status: NEW
Alias: CVE-2026-97595
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-25 10:54 UTC by OSIDB Bzimport
Modified: 2026-09-29 11:08 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-09-25 10:54:51 UTC
In the Linux kernel, the following vulnerability has been resolved:

mac802154: fix use-after-free of sdata via queued RX frames

The RX softirq producer ieee802154_subif_frame() queues received beacon
and MAC-command frames onto local->rx_beacon_list / rx_mac_cmd_list and
schedules a process-context worker, storing a raw mac_pkt->sdata (and
skb->dev == sdata->dev) with neither a reference nor any locking:

 - the lists have no lock: the softirq producer list_add_tail()s while the
   mac_wq worker list_del()s, so sibling interfaces on the same phy corrupt
   the list;

 - the workers dereference the interface after it may have been freed.
   mac802154_rx_mac_cmd_worker() touches mac_pkt->sdata directly, and
   mac802154_rx_beacon_worker() -> mac802154_process_beacon() dereferences
   skb->dev (== sdata->dev). Removing an interface frees its sdata
   (netdev_priv) while a queued frame still points at it, so a later worker
   run is a use-after-free.

Reproduced under KASAN by flooding a victim interface with MAC command
frames and removing it (the beacon path is the same class via skb->dev):

  BUG: KASAN: slab-use-after-free in mac802154_rx_mac_cmd_worker+0x463/0x630 [mac802154]
  Read of size 4 at addr ffff888002f9ea18 by task kworker/u8:1/31
  Workqueue: phy0-mac-cmds mac802154_rx_mac_cmd_worker [mac802154]
  Call Trace:
   mac802154_rx_mac_cmd_worker+0x463/0x630 [mac802154]
   process_one_work+0x611/0xe80
   worker_thread+0x52e/0xdc0
   kthread+0x30c/0x630
   ret_from_fork+0x2fd/0x3e0

Fix both lists together:

 - add local->rx_lock and take it around every list access: the softirq
   producer (plain spin_lock, softirq context) and the workers and flush
   (spin_lock_bh, process context);

 - pin the interface for the lifetime of a queued frame with
   netdev_hold()/netdev_put(), so the worker can safely dereference sdata /
   skb->dev even while the interface is being removed;

 - dequeue under the lock at the head and loop-drain the whole list in the
   workers (they previously processed one frame per run and relied on a
   later enqueue to drain the rest);

 - drop not-yet-started frames of an interface before it is unregistered,
   from ieee802154_if_remove() (after the RCU grace period) and from the
   ieee802154_remove_interfaces() loop -- the latter is the whole-phy
   teardown path, which does not go through ieee802154_if_remove().

An in-flight worker that already dequeued a frame keeps its own netdev
reference; unregister_netdevice() then waits it out in netdev_run_todo(),
which runs at rtnl_unlock() (rtnl released) and after the interface has
been closed, so it does not pin rtnl. A worker blocked in an association
TX only delays that one interface's unregister (the usual "waiting for %s
to become free"), it does not hold rtnl. netdev_hold() is used for this
reason instead of a cancel_work_sync() under rtnl, which would block on
the worker's unbounded MLME TX wait via ieee802154_sync_queue().

The mac-command worker additionally skips processing for a stopped
interface (ieee802154_sdata_running()), avoiding a needless association
response during teardown.


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