CVE-2021-47146

/// Technical description

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

mld: fix panic in mld_newpack()

mld_newpack() doesn't allow to allocate high order page,

only order-0 allocation is allowed.

If headroom size is too large, a kernel panic could occur in skb_put().

Test commands:

ip netns del A

ip netns del B

ip netns add A

ip netns add B

ip link add veth0 type veth peer name veth1

ip link set veth0 netns A

ip link set veth1 netns B

ip netns exec A ip link set lo up

ip netns exec A ip link set veth0 up

ip netns exec A ip -6 a a 2001:db8:0::1/64 dev veth0

ip netns exec B ip link set lo up

ip netns exec B ip link set veth1 up

ip netns exec B ip -6 a a 2001:db8:0::2/64 dev veth1

for i in {1..99}

do

let A=$i-1

ip netns exec A ip link add ip6gre$i type ip6gre \

local 2001:db8:$A::1 remote 2001:db8:$A::2 encaplimit 100

ip netns exec A ip -6 a a 2001:db8:$i::1/64 dev ip6gre$i

ip netns exec A ip lin

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References