In the Linux kernel, the following vulnerability has been resolved:

mac80211: fix potential double free on mesh join

While commit 6a01afcf8468 ("mac80211: mesh: Free ie data when leaving
mesh") fixed a memory leak on mesh leave / teardown it introduced a
potential memory corruption caused by a double free when rejoining the
mesh:

  ieee80211_leave_mesh()
  -> kfree(sdata->u.mesh.ie);
  ...
  ieee80211_join_mesh()
  -> copy_mesh_setup()
     -> old_ie = ifmsh->ie;
     -> kfree(old_ie);

This double free / kernel panics can be reproduced by using wpa_supplicant
with an encrypted mesh (if set up without encryption via "iw" then
ifmsh->ie is always NULL, which avoids this issue). And then calling:

  $ iw dev mesh0 mesh leave
  $ iw dev mesh0 mesh join my-mesh

Note that typically these commands are not used / working when using
wpa_supplicant. And it seems that wpa_supplicant or wpa_cli are going
through a NETDEV_DOWN/NETDEV_UP cycle between a mesh leave and mesh join
where the NETDEV_UP resets the mesh.ie to NULL via a memcpy of
default_mesh_setup in cfg80211_netdev_notifier_call, which then avoids
the memory corruption, too.

The issue was first observed in an application which was not using
wpa_supplicant but "Senf" instead, which implements its own calls to
nl80211.

Fixing the issue by removing the kfree()'ing of the mesh IE in the mesh
join function and leaving it solely up to the mesh leave to free the
mesh IE.

https://git.kernel.org/stable/c/12e407a8ef17623823fd0c066fbd7f103953d28d

https://git.kernel.org/stable/c/273ebddc5fda2967492cb0b6cdd7d81cfb821b76

https://git.kernel.org/stable/c/3bbd0000d012f92aec423b224784fbf0f7bf40f8

https://git.kernel.org/stable/c/46bb87d40683337757a2f902fcd4244b32bb4e86

https://git.kernel.org/stable/c/4a2d4496e15ea5bb5c8e83b94ca8ca7fb045e7d3

https://git.kernel.org/stable/c/582d8c60c0c053684f7138875e8150d5749ffc17

https://git.kernel.org/stable/c/5d3ff9542a40ce034416bca03864709540a36016

https://git.kernel.org/stable/c/615716af8644813355e014314a0bc1e961250f5a

https://git.kernel.org/stable/c/c1d9c3628ef0a0ca197595d0f9e01cd3b5dda186