CVE-2026-64569 mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=n

Not scored Published 5 Aug 2026 Updated 19 Aug 2026

An unprivileged local user can cause a kernel crash via a NULL pointer dereference in MPLS route dumping when IPv4 support is disabled.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-64569?

CVE-2026-64569 is a vulnerability in Linux, published on 5 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=n

On CONFIG_INET=n builds, mpls_valid_fib_dump_req() walks the parsed attribute table itself instead of calling ip_valid_fib_dump_req(). The RTA_OIF arm passes tb[RTA_OIF] to nla_get_u32() without checking it is present, so an RTM_GETROUTE dump for AF_MPLS with strict checking and no RTA_OIF hits a NULL dereference.

RTM_GETROUTE is RTNL_KIND_GET, which rtnetlink_rcv_msg() permits without CAP_NET_ADMIN, so an unprivileged user can trigger it.

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:mpls_valid_fib_dump_req (net/mpls/af_mpls.c:2189) Call Trace: mpls_dump_routes (net/mpls/af_mpls.c:2236) netlink_dump (net/netlink/af_netlink.c:2331) __netlink_dump_start (net/netlink/af_netlink.c:2446) rtnetlink_rcv_msg (net/core/rtnetlink.c:7033) netlink_rcv_skb (net/netlink/af_netlink.c:2556) netlink_unicast (net/netlink/af_netlink.c:1345) netlink_sendmsg (net/netlink/af_netlink.c:1900) __sock_sendmsg (net/socket.c:790) ____sys_sendmsg (net/socket.c:2684) ___sys_sendmsg (net/socket.c:2738) __sys_sendmsg (net/socket.c:2770) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)

Skip unset attributes, as ip_valid_fib_dump_req() does.

Which versions are affected by CVE-2026-64569?

How do I fix CVE-2026-64569?

Apply the vendor's patch.

Is CVE-2026-64569 being exploited?

There is no known exploitation of CVE-2026-64569 in the wild and no public exploit code.

Sources

Also known as AZL-94479, BELL-CVE-2026-64569, DEBIAN-CVE-2026-64569, GHSA-4gx4-c274-rxvr, UBUNTU-CVE-2026-64569.