CVE-2026-23173 net/mlx5e: TC, delete flows only for existing peers
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: TC, delete flows only for existing peers

When deleting TC steering flows, iterate only over actual devcom
peers instead of assuming all possible ports exist. This avoids
touching non-existent peers and ensures cleanup is limited to
devices the driver is currently connected to.

 BUG: kernel NULL pointer dereference, address: 0000000000000008
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page
 PGD 133c8a067 P4D 0
 Oops: Oops: 0002 [#1] SMP
 CPU: 19 UID: 0 PID: 2169 Comm: tc Not tainted 6.18.0+ #156 NONE
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
 RIP: 0010:mlx5e_tc_del_fdb_peers_flow+0xbe/0x200 [mlx5_core]
 Code: 00 00 a8 08 74 a8 49 8b 46 18 f6 c4 02 74 9f 4c 8d bf a0 12 00 00 4c 89 ff e8 0e e7 96 e1 49 8b 44 24 08 49 8b 0c 24 4c 89 ff <48> 89 41 08 48 89 08 49 89 2c 24 49 89 5c 24 08 e8 7d ce 96 e1 49
 RSP: 0018:ff11000143867528 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: dead000000000122 RCX: 0000000000000000
 RDX: ff11000143691580 RSI: ff110001026e5000 RDI: ff11000106f3d2a0
 RBP: dead000000000100 R08: 00000000000003fd R09: 0000000000000002
 R10: ff11000101c75690 R11: ff1100085faea178 R12: ff11000115f0ae78
 R13: 0000000000000000 R14: ff11000115f0a800 R15: ff11000106f3d2a0
 FS:  00007f35236bf740(0000) GS:ff110008dc809000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000008 CR3: 0000000157a01001 CR4: 0000000000373eb0
 Call Trace:
  <TASK>
  mlx5e_tc_del_flow+0x46/0x270 [mlx5_core]
  mlx5e_flow_put+0x25/0x50 [mlx5_core]
  mlx5e_delete_flower+0x2a6/0x3e0 [mlx5_core]
  tc_setup_cb_reoffload+0x20/0x80
  fl_reoffload+0x26f/0x2f0 [cls_flower]
  ? mlx5e_tc_reoffload_flows_work+0xc0/0xc0 [mlx5_core]
  ? mlx5e_tc_reoffload_flows_work+0xc0/0xc0 [mlx5_core]
  tcf_block_playback_offloads+0x9e/0x1c0
  tcf_block_unbind+0x7b/0xd0
  tcf_block_setup+0x186/0x1d0
  tcf_block_offload_cmd.isra.0+0xef/0x130
  tcf_block_offload_unbind+0x43/0x70
  __tcf_block_put+0x85/0x160
  ingress_destroy+0x32/0x110 [sch_ingress]
  __qdisc_destroy+0x44/0x100
  qdisc_graft+0x22b/0x610
  tc_get_qdisc+0x183/0x4d0
  rtnetlink_rcv_msg+0x2d7/0x3d0
  ? rtnl_calcit.isra.0+0x100/0x100
  netlink_rcv_skb+0x53/0x100
  netlink_unicast+0x249/0x320
  ? __alloc_skb+0x102/0x1f0
  netlink_sendmsg+0x1e3/0x420
  __sock_sendmsg+0x38/0x60
  ____sys_sendmsg+0x1ef/0x230
  ? copy_msghdr_from_user+0x6c/0xa0
  ___sys_sendmsg+0x7f/0xc0
  ? ___sys_recvmsg+0x8a/0xc0
  ? __sys_sendto+0x119/0x180
  __sys_sendmsg+0x61/0xb0
  do_syscall_64+0x55/0x640
  entry_SYSCALL_64_after_hwframe+0x4b/0x53
 RIP: 0033:0x7f35238bb764
 Code: 15 b9 86 0c 00 f7 d8 64 89 02 b8 ff ff ff ff eb bf 0f 1f 44 00 00 f3 0f 1e fa 80 3d e5 08 0d 00 00 74 13 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 4c c3 0f 1f 00 55 48 89 e5 48 83 ec 20 89 55
 RSP: 002b:00007ffed4c35638 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
 RAX: ffffffffffffffda RBX: 000055a2efcc75e0 RCX: 00007f35238bb764
 RDX: 0000000000000000 RSI: 00007ffed4c356a0 RDI: 0000000000000003
 RBP: 00007ffed4c35710 R08: 0000000000000010 R09: 00007f3523984b20
 R10: 0000000000000004 R11: 0000000000000202 R12: 00007ffed4c35790
 R13: 000000006947df8f R14: 000055a2efcc75e0 R15: 00007ffed4c35780
CVSS v3.1 score: 5.5