Vulnerability CVE-2021-47109
Published: 2024-03-15

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

neighbour: allow NUD_NOARP entries to be forced GCed

IFF_POINTOPOINT interfaces use NUD_NOARP entries for IPv6. It's possible to
fill up the neighbour table with enough entries that it will overflow for
valid connections after that.

This behaviour is more prevalent after commit 58956317c8de ("neighbor:
Improve garbage collection") is applied, as it prevents removal from
entries that are not NUD_FAILED, unless they are more than 5s old.

 References:
https://git.kernel.org/stable/c/d99029e6aab62aef0a0251588b2867e77e83b137
https://git.kernel.org/stable/c/d17d47da59f726dc4c87caebda3a50333d7e2fd3
https://git.kernel.org/stable/c/ddf088d7aaaaacfc836104f2e632b29b1d383cfc
https://git.kernel.org/stable/c/7a6b1ab7475fd6478eeaf5c9d1163e7a18125c8f
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