Linux kernel: IPv6 rpfilter NULL deref crash via faulty route lookup
CVE-2026-98379 Published on October 9, 2026
netfilter: ip6t_rpfilter: reject routes without inet6_dev
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ip6t_rpfilter: reject routes without inet6_dev
ip6_route_lookup() can return an error-free route whose rt6i_idev is
NULL. Lowering an external nexthop device's MTU below IPV6_MIN_MTU tears
down its inet6_dev while fib6_ifdown() leaves routes using nexthop objects
in the FIB. An unprivileged user can construct this state with rtnetlink
in a private user and network namespace, then trigger a NULL dereference
through an IPv6 rpfilter lookup:
Oops: general protection fault, probably for non-canonical address
0xdffffc0000000000
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: rpfilter_mt (net/ipv6/netfilter/ip6t_rpfilter.c:75)
Call Trace:
ip6t_do_table (net/ipv6/netfilter/ip6_tables.c:316)
nf_hook_slow (net/netfilter/core.c:619)
ipv6_rcv (net/ipv6/ip6_input.c:351)
__netif_receive_skb_one_core (net/core/dev.c:6216)
process_backlog (net/core/dev.c:6680)
__napi_poll (net/core/dev.c:7739)
net_rx_action (net/core/dev.c:7959)
handle_softirqs (kernel/softirq.c:622)
do_softirq.part.0 (kernel/softirq.c:523)
__local_bh_enable_ip (kernel/softirq.c:450)
__dev_queue_xmit (net/core/dev.c:4913)
packet_sendmsg (net/packet/af_packet.c:3139)
__sys_sendto (net/socket.c:2252)
__x64_sys_sendto (net/socket.c:2259)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Kernel panic - not syncing: Fatal exception in interrupt
Reject routes without an inet6_dev immediately after lookup. Such routes
are not eligible for reverse-path filtering, and the check protects all
later rt6i_idev dereferences.
Products Associated with CVE-2026-98379
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Affected Versions
Linux:- Version e26f9a480fb6c1b614660e824d69a74e2ce990f3 and below f4de78756b0fddbd125b2b1b77c74f2eccc8e977 is affected.
- Version e26f9a480fb6c1b614660e824d69a74e2ce990f3 and below 1681ab6dd1271f2f36047490793b78b1848bbcc9 is affected.
- Version e26f9a480fb6c1b614660e824d69a74e2ce990f3 and below 65487e9e99431ffcf05024a817f51ee4e3bd9b47 is affected.
- Version e26f9a480fb6c1b614660e824d69a74e2ce990f3 and below f49da48bd679cfee646d6a40dd02b1933de577d1 is affected.
- Version e26f9a480fb6c1b614660e824d69a74e2ce990f3 and below 290c96e5d9471d1ded9ab1e8ffbb04f6ee7b0f40 is affected.
- Version e26f9a480fb6c1b614660e824d69a74e2ce990f3 and below eafe081ea77d25b5c8e601680671b4ecb4520e7d is affected.
- Version e26f9a480fb6c1b614660e824d69a74e2ce990f3 and below 3a7384bc2e66217c9a01a392281334f4423740a0 is affected.
- Version e26f9a480fb6c1b614660e824d69a74e2ce990f3 and below 1b9b5323725e458906c7620a3bc10398b51ad954 is affected.
- Version 3.3 is affected.
- Before 3.3 is unaffected.
- Version 5.10.271, <= 5.10.* is unaffected.
- Version 5.15.222, <= 5.15.* is unaffected.
- Version 6.1.189, <= 6.1.* is unaffected.
- Version 6.6.158, <= 6.6.* is unaffected.
- Version 6.12.112, <= 6.12.* is unaffected.
- Version 6.18.55, <= 6.18.* is unaffected.
- Version 7.2.9, <= 7.2.* is unaffected.
- Version 7.3-rc5, <= * is unaffected.