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Linux Kernel: Deleting Network Flows Can Cause Crash
CVE-2026-23173
Summary
A bug in the Linux kernel's network management system could cause a crash when deleting network flow settings on a certain type of network hardware. This issue has been fixed, so you don't need to take any action. However, if you're using the affected hardware and have not updated your Linux kernel, you should update it as soon as possible to prevent any potential crashes.
Original title
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 inst...
Original description
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
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
Published: 14 Feb 2026 · Updated: 10 Mar 2026 · First seen: 6 Mar 2026