CVE-2026-22993

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

idpf: Fix RSS LUT NULL ptr issue after soft reset

During soft reset, the RSS LUT is freed and not restored unless the interface is up. If an ethtool command that accesses the rss lut is attempted immediately after reset, it will result in NULL ptr dereference. Also, there is no need to reset the rss lut if the soft reset does not involve queue count change.

After soft reset, set the RSS LUT to default values based on the updated queue count only if the reset was a result of a queue count change and the LUT was not configured by the user. In all other cases, don't touch the LUT.

Steps to reproduce:

** Bring the interface down (if up) ifconfig eth1 down

** update the queue count (eg., 27->20) ethtool -L eth1 combined 20

** display the RSS LUT ethtool -x eth1

[82375.558338] BUG: kernel NULL pointer dereference, address: 0000000000000000 [82375.558373] #PF: supervisor read access in kernel mode [82375.558391] #PF: error_code(0x0000) - not-present page [82375.558408] PGD 0 P4D 0 [82375.558421] Oops: Oops: 0000 [#1] SMP NOPTI <snip> [82375.558516] RIP: 0010:idpf_get_rxfh+0x108/0x150 [idpf] [82375.558786] Call Trace: [82375.558793] <TASK> [82375.558804] rss_prepare.isra.0+0x187/0x2a0 [82375.558827] rss_prepare_data+0x3a/0x50 [82375.558845] ethnl_default_doit+0x13d/0x3e0 [82375.558863] genl_family_rcv_msg_doit+0x11f/0x180 [82375.558886] genl_rcv_msg+0x1ad/0x2b0 [82375.558902] ? __pfx_ethnl_default_doit+0x10/0x10 [82375.558920] ? __pfx_genl_rcv_msg+0x10/0x10 [82375.558937] netlink_rcv_skb+0x58/0x100 [82375.558957] genl_rcv+0x2c/0x50 [82375.558971] netlink_unicast+0x289/0x3e0 [82375.558988] netlink_sendmsg+0x215/0x440 [82375.559005] __sys_sendto+0x234/0x240 [82375.559555] __x64_sys_sendto+0x28/0x30 [82375.560068] x64_sys_call+0x1909/0x1da0 [82375.560576] do_syscall_64+0x7a/0xfa0 [82375.561076] ? clear_bhb_loop+0x60/0xb0 [82375.561567] entry_SYSCALL_64_after_hwframe+0x76/0x7e <snip>

A NULL pointer dereference can be triggered in the idpf driver when an ethtool command accesses the RSS indirection table immediately after a soft reset, as the RSS LUT may have been freed but not reinitialized. This results in a reliable kernel crash and constitutes a local denial-of-service condition, typically requiring CAP_NET_ADMIN privileges.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.