In the Linux kernel, the following vulnerability has been resolved:
ipv6: Add lwtunnel encap size of all siblings in nexthop calculation
In function rt6_nlmsg_size(), the length of nexthop is calculated
by multipling the nexthop length of fib6_info and the number of
siblings. However if the fib6_info has no lwtunnel but the siblings
have lwtunnels, the nexthop length is less than it should be, and
it will trigger a warning in inet6_rt_notify() as follows:
WARNING: CPU: 0 PID: 6082 at net/ipv6/route.c:6180 inet6_rt_notify+0x120/0x130
......
Call Trace:
<TASK>
fib6_add_rt2node+0x685/0xa30
fib6_add+0x96/0x1b0
ip6_route_add+0x50/0xd0
inet6_rtm_newroute+0x97/0xa0
rtnetlink_rcv_msg+0x156/0x3d0
netlink_rcv_skb+0x5a/0x110
netlink_unicast+0x246/0x350
netlink_sendmsg+0x250/0x4c0
sock_sendmsg+0x66/0x70
___sys_sendmsg+0x7c/0xd0
__sys_sendmsg+0x5d/0xb0
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
This bug can be reproduced by script:
ip -6 addr add 2002::2/64 dev ens2
ip -6 route add 100::/64 via 2002::1 dev ens2 metric 100
for i in 10 20 30 40 50 60 70;
do
ip link add link ens2 name ipv_$i type ipvlan
ip -6 addr add 2002::$i/64 dev ipv_$i
ifconfig ipv_$i up
done
for i in 10 20 30 40 50 60;
do
ip -6 route append 100::/64 encap ip6 dst 2002::$i via 2002::1
dev ipv_$i metric 100
done
ip -6 route append 100::/64 via 2002::1 dev ipv_70 metric 100
This patch fixes it by adding nexthop_len of every siblings using
rt6_nh_nlmsg_size().
References
Configurations
Configuration 1 (hide)
|
History
20 Jan 2026, 16:41
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| First Time |
Linux
Linux linux Kernel |
|
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| CWE | NVD-CWE-noinfo | |
| References | () https://git.kernel.org/stable/c/4cc59f386991ec9374cb4bc83dbe1c0b5a95033f - Patch | |
| References | () https://git.kernel.org/stable/c/aa75d826c221e8d48607aef33836cf872a159cf1 - Patch | |
| References | () https://git.kernel.org/stable/c/aba298b35619213ca787d08d472049627d8cd012 - Patch | |
| References | () https://git.kernel.org/stable/c/da26369377f0b671c14692e2d65ceb38131053e1 - Patch | |
| References | () https://git.kernel.org/stable/c/dcdddb5f490890d058ea1f194d661219e92fe88d - Patch | |
| References | () https://git.kernel.org/stable/c/e11e4d524eba2d3c8fdf897d7ce3853f7573bae9 - Patch |
01 Oct 2025, 12:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-10-01 12:15
Updated : 2026-01-20 16:41
NVD link : CVE-2023-53477
Mitre link : CVE-2023-53477
CVE.ORG link : CVE-2023-53477
JSON object : View
Products Affected
linux
- linux_kernel
CWE