CVE-2026-23385

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

netfilter: nf_tables: clone set on flush only

Syzbot with fault injection triggered a failing memory allocation with

GFP_KERNEL which results in a WARN splat:

iter.err

WARNING: net/netfilter/nf_tables_api.c:845 at nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845, CPU#0: syz.0.17/5992

Modules linked in:

CPU: 0 UID: 0 PID: 5992 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026

RIP: 0010:nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845

Code: 8b 05 86 5a 4e 09 48 3b 84 24 a0 00 00 00 75 62 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 63 6d fa f7 90 <0f> 0b 90 43

+80 7c 35 00 00 0f 85 23 fe ff ff e9 26 fe ff ff 89 d9

RSP: 0018:ffffc900045af780 EFLAGS: 00010293

RAX: ffffffff89ca45bd RBX: 00000000fffffff4 RCX: ffff888028111e40

RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000000

RBP: ffffc900045af870 R08: 0000000000400dc0 R09: 00000000ffffffff

R10: dffffc0000000000 R11: fffffbfff1d141db R12: ffffc900045af7e0

R13: 1ffff920008b5f24 R14: dffffc0000000000 R15: ffffc900045af920

FS: 000055557a6a5500(0000) GS:ffff888125496000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007fb5ea271fc0 CR3: 000000003269e000 CR4: 00000000003526f0

Call Trace:

<TASK>

__nft_release_table+0xceb/0x11f0 net/netfilter/nf_tables_api.c:12115

nft_rcv_nl_event+0xc25/0xdb0 net/netfilter/nf_tables_api.c:12187

notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85

blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380

netlink_release+0x123b/0x1ad0 net/netlink/af_netlink.c:761

__sock_release net/socket.c:662 [inline]

sock_close+0xc3/0x240 net/socket.c:1455

Restrict set clone to the flush set command in the preparation phase.

Add NFT_ITER_UPDATE_CLONE and use it for this purpose, update the rbtree

and pipapo backends to only clone the set when this iteration type is

used.

As for the existing NFT_ITER_UPDATE type, update the pipapo backend to

use the existing set clone if available, otherwise use the existing set

representation. After this update, there is no need to clone a set that

is being deleted, this includes bound anonymous set.

An alternative approach to NFT_ITER_UPDATE_CLONE is to add a .clone

interface and call it from the flush set path.