CVE-2026-22985: idpf: Fix RSS LUT NULL pointer crash on early ethtool operations

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-23 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: idpf: Fix RSS LUT NULL pointer crash on early ethtool operations The RSS LUT is not initialized until the interface comes up, causing the following NULL pointer crash when ethtool operations like rxhash on/off are performed before the interface is brought up for the first time. Move RSS LUT initialization from ndo_open to vport creation to ensure LUT is always available. This enables RSS configuration via ethtool before bringing the interface up. Simplify LUT management by maintaining all changes in the driver's soft copy and programming zeros to the indirection table when rxhash is disabled. Defer HW programming until the interface comes up if it is down during rxhash and LUT configuration changes. Steps to reproduce: ** Load idpf driver; interfaces will be created modprobe idpf ** Before bringing the interfaces up, turn rxhash off ethtool -K eth2 rxhash off [89408.371875] BUG: kernel NULL pointer dereference, address: 0000000000000000 [89408.371908] #PF: supervisor read access in kernel mode [89408.371924] #PF: error_code(0x0000) - not-present page [89408.371940] PGD 0 P4D 0 [89408.371953] Oops: Oops: 0000 [#1] SMP NOPTI <snip> [89408.372052] RIP: 0010:memcpy_orig+0x16/0x130 [89408.372310] Call Trace: [89408.372317] <TASK> [89408.372326] ? idpf_set_features+0xfc/0x180 [idpf] [89408.372363] __netdev_update_features+0x295/0xde0 [89408.372384] ethnl_set_features+0x15e/0x460 [89408.372406] genl_family_rcv_msg_doit+0x11f/0x180 [89408.372429] genl_rcv_msg+0x1ad/0x2b0 [89408.372446] ? __pfx_ethnl_set_features+0x10/0x10 [89408.372465] ? __pfx_genl_rcv_msg+0x10/0x10 [89408.372482] netlink_rcv_skb+0x58/0x100 [89408.372502] genl_rcv+0x2c/0x50 [89408.372516] netlink_unicast+0x289/0x3e0 [89408.372533] netlink_sendmsg+0x215/0x440 [89408.372551] __sys_sendto+0x234/0x240 [89408.372571] __x64_sys_sendto+0x28/0x30 [89408.372585] x64_sys_call+0x1909/0x1da0 [89408.372604] do_syscall_64+0x7a/0xfa0 [89408.373140] ? clear_bhb_loop+0x60/0xb0 [89408.373647] entry_SYSCALL_64_after_hwframe+0x76/0x7e [89408.378887] </TASK> <snip>

Affected products

Linux kernel: from 6.7 before 6.18.6; 6.19-rc1, 6.19-rc2, 6.19-rc3, 6.19-rc4 — fixed in 6.18.6

How to fix

Upgrade to a fixed version: Linux kernel 6.18.6. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-22985 or the next vulnerability affects your stack