CVE-2026-98849 pfcp: fix socket lifetime on netdevice registration failure
A local attacker can trigger a kernel crash via a double-free scenario in the PFCP module when netdevice registration fails.
- 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-2026-98849?
CVE-2026-98849 is a vulnerability in Linux, published on 18 Oct 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:
pfcp: fix socket lifetime on netdevice registration failure
pfcp_newlink() creates the UDP socket before register_netdevice(). If registration fails after pfcp_dev_init() succeeds, the core calls pfcp_dev_uninit(), which releases the socket and clears pfcp->sk. The newlink error path then releases it again, causing a NULL pointer dereference. This was observed with failslab fault injection:
FAULT_INJECTION: forcing a failure. kobject: kobject_add_internal failed for pfcp0 (error: -12 parent: net) BUG: KASAN: null-ptr-deref in udp_tunnel_sock_release+0x1c/0x50 Read of size 8 at addr 0000000000000120 by task ip/1037 Call trace: show_stack+0x18/0x24 (C) dump_stack_lvl+0x78/0x90 print_report+0x468/0x5cc kasan_report+0xa4/0xf0 __asan_load8+0x7c/0xd0 udp_tunnel_sock_release+0x1c/0x50 pfcp_newlink+0x128/0x184 rtnl_newlink+0x848/0xe44 rtnetlink_rcv_msg+0x468/0x514 netlink_rcv_skb+0xc0/0x1f0 rtnetlink_rcv+0x18/0x24 netlink_unicast+0x4b8/0x558 netlink_sendmsg+0x2b8/0x584 ...
Return from pfcp_del_sock() if pfcp->sk is NULL.
Which versions are affected by CVE-2026-98849?
How do I fix CVE-2026-98849?
Apply the vendor's patch.
Is CVE-2026-98849 being exploited?
There is no known exploitation of CVE-2026-98849 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-98849, DEBIAN-CVE-2026-98849, GHSA-gh42-phxg-w86j, UBUNTU-CVE-2026-98849.