CVE-2023-54216
Description
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: TC, Fix using eswitch mapping in nic mode
Cited patch is using the eswitch object mapping pool while in nic mode where it isn't initialized. This results in the trace below [0].
Fix that by using either nic or eswitch object mapping pool depending if eswitch is enabled or not.
[0]: [ 826.446057] ================================================================== [ 826.446729] BUG: KASAN: slab-use-after-free in mlx5_add_flow_rules+0x30/0x490 [mlx5_core] [ 826.447515] Read of size 8 at addr ffff888194485830 by task tc/6233
[ 826.448243] CPU: 16 PID: 6233 Comm: tc Tainted: G W 6.3.0-rc6+ #1 [ 826.448890] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 826.449785] Call Trace: [ 826.450052] [ 826.450302] dump_stack_lvl+0x33/0x50 [ 826.450650] print_report+0xc2/0x610 [ 826.450998] ? __virt_addr_valid+0xb1/0x130 [ 826.451385] ? mlx5_add_flow_rules+0x30/0x490 [mlx5_core] [ 826.451935] kasan_report+0xae/0xe0 [ 826.452276] ? mlx5_add_flow_rules+0x30/0x490 [mlx5_core] [ 826.452829] mlx5_add_flow_rules+0x30/0x490 [mlx5_core] [ 826.453368] ? __kmalloc_node+0x5a/0x120 [ 826.453733] esw_add_restore_rule+0x20f/0x270 [mlx5_core] [ 826.454288] ? mlx5_eswitch_add_send_to_vport_meta_rule+0x260/0x260 [mlx5_core] [ 826.455011] ? mutex_unlock+0x80/0xd0 [ 826.455361] ? __mutex_unlock_slowpath.constprop.0+0x210/0x210 [ 826.455862] ? mapping_add+0x2cb/0x440 [mlx5_core] [ 826.456425] mlx5e_tc_action_miss_mapping_get+0x139/0x180 [mlx5_core] [ 826.457058] ? mlx5e_tc_update_skb_nic+0xb0/0xb0 [mlx5_core] [ 826.457636] ? __kasan_kmalloc+0x77/0x90 [ 826.458000] ? __kmalloc+0x57/0x120 [ 826.458336] mlx5_tc_ct_flow_offload+0x325/0xe40 [mlx5_core] [ 826.458916] ? ct_kernel_enter.constprop.0+0x48/0xa0 [ 826.459360] ? mlx5_tc_ct_parse_action+0xf0/0xf0 [mlx5_core] [ 826.459933] ? mlx5e_mod_hdr_attach+0x491/0x520 [mlx5_core] [ 826.460507] ? mlx5e_mod_hdr_get+0x12/0x20 [mlx5_core] [ 826.461046] ? mlx5e_tc_attach_mod_hdr+0x154/0x170 [mlx5_core] [ 826.461635] mlx5e_configure_flower+0x969/0x2110 [mlx5_core] [ 826.462217] ? _raw_spin_lock_bh+0x85/0xe0 [ 826.462597] ? __mlx5e_add_fdb_flow+0x750/0x750 [mlx5_core] [ 826.463163] ? kasan_save_stack+0x2e/0x40 [ 826.463534] ? down_read+0x115/0x1b0 [ 826.463878] ? down_write_killable+0x110/0x110 [ 826.464288] ? tc_setup_action.part.0+0x9f/0x3b0 [ 826.464701] ? mlx5e_is_uplink_rep+0x4c/0x90 [mlx5_core] [ 826.465253] ? mlx5e_tc_reoffload_flows_work+0x130/0x130 [mlx5_core] [ 826.465878] tc_setup_cb_add+0x112/0x250 [ 826.466247] fl_hw_replace_filter+0x230/0x310 [cls_flower] [ 826.466724] ? fl_hw_destroy_filter+0x1a0/0x1a0 [cls_flower] [ 826.467212] fl_change+0x14e1/0x2030 [cls_flower] [ 826.467636] ? sock_def_readable+0x89/0x120 [ 826.468019] ? fl_tmplt_create+0x2d0/0x2d0 [cls_flower] [ 826.468509] ? kasan_unpoison+0x23/0x50 [ 826.468873] ? get_random_u16+0x180/0x180 [ 826.469244] ? __radix_tree_lookup+0x2b/0x130 [ 826.469640] ? fl_get+0x7b/0x140 [cls_flower] [ 826.470042] ? fl_mask_put+0x200/0x200 [cls_flower] [ 826.470478] ? __mutex_unlock_slowpath.constprop.0+0x210/0x210 [ 826.470973] ? fl_tmplt_create+0x2d0/0x2d0 [cls_flower] [ 826.471427] tc_new_tfilter+0x644/0x1050 [ 826.471795] ? tc_get_tfilter+0x860/0x860 [ 826.472170] ? __thaw_task+0x130/0x130 [ 826.472525] ? arch_stack_walk+0x98/0xf0 [ 826.472892] ? cap_capable+0x9f/0xd0 [ 826.473235] ? security_capable+0x47/0x60 [ 826.473608] rtnetlink_rcv_msg+0x1d5/0x550 [ 826.473985] ? rtnl_calcit.isra.0+0x1f0/0x1f0 [ 826.474383] ? __stack_depot_save+0x35/0x4c0 [ 826.474779] ? kasan_save_stack+0x2e/0x40 [ 826.475149] ? kasan_save_stack+0x1e/0x40 [ 826.475518] ? __kasan_record_aux_stack+0x9f/0xb0 [ 826.475939] ? task_work_add+0x77/0x1c0 [ 826.476305] netlink_rcv_skb+0xe0/0x210 ---truncated---
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Linux kernel net/mlx5e TC code incorrectly uses eswitch mapping in NIC-only mode, causing a slab-use-after-free crash.
Root
Cause The vulnerability occurs because the net/mlx5e TC driver invokes the eswitch mapping pool (esw_add_restore_rule) even when the device is in NIC (Network Interface Card) mode, where the eswitch structures are not initialized. This leads to a slab-use-after-free condition when mlx5_add_flow_rules accesses freed memory [1].
Attack
Vector An attacker who can trigger TC traffic control operations on a system with affected mlx5_core driver (e.g., by setting up certain TC rules) can cause the kernel to read from a freed memory region. The trace shows the crash occurs during tc command execution, indicating a local user with sufficient privileges can trigger this flaw [1].
Impact
The bug leads to a kernel crash (KASAN report) and denial of service. The CVSS score may be high due to the potential for system instability. No remote exploitation path is described, but local unprivileged users might leverage TC netlink sockets to hit the vulnerable code path.
Mitigation
The fix distinguishes between NIC and eswitch modes by selecting the appropriate object mapping pool. The patch was committed to the Linux stable tree [1]. Users should update to a kernel version containing commit dfa1e46d6093 or later.
AI Insight generated on May 19, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
1Patches
24150441c010ddfa1e46d6093Vulnerability mechanics
Generated on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
2News mentions
0No linked articles in our index yet.