CVE-2025-40238
Description
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Fix IPsec cleanup over MPV device
When we do mlx5e_detach_netdev() we eventually disable blocking events notifier, among those events are IPsec MPV events from IB to core.
So before disabling those blocking events, make sure to also unregister the devcom device and mark all this device operations as complete, in order to prevent the other device from using invalid netdev during future devcom events which could cause the trace below.
BUG: kernel NULL pointer dereference, address: 0000000000000010 PGD 146427067 P4D 146427067 PUD 146488067 PMD 0 Oops: Oops: 0000 [#1] SMP CPU: 1 UID: 0 PID: 7735 Comm: devlink Tainted: GW 6.12.0-rc6_for_upstream_min_debug_2024_11_08_00_46 #1 Tainted: [W]=WARN Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:mlx5_devcom_comp_set_ready+0x5/0x40 [mlx5_core] Code: 00 01 48 83 05 23 32 1e 00 01 41 b8 ed ff ff ff e9 60 ff ff ff 48 83 05 00 32 1e 00 01 eb e3 66 0f 1f 44 00 00 0f 1f 44 00 00 <48> 8b 47 10 48 83 05 5f 32 1e 00 01 48 8b 50 40 48 85 d2 74 05 40 RSP: 0018:ffff88811a5c35f8 EFLAGS: 00010206 RAX: ffff888106e8ab80 RBX: ffff888107d7e200 RCX: ffff88810d6f0a00 RDX: ffff88810d6f0a00 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff88811a17e620 R08: 0000000000000040 R09: 0000000000000000 R10: ffff88811a5c3618 R11: 0000000de85d51bd R12: ffff88811a17e600 R13: ffff88810d6f0a00 R14: 0000000000000000 R15: ffff8881034bda80 FS: 00007f27bdf89180(0000) GS:ffff88852c880000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 000000010f159005 CR4: 0000000000372eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace:
? __die+0x20/0x60 ? page_fault_oops+0x150/0x3e0 ? exc_page_fault+0x74/0x130 ? asm_exc_page_fault+0x22/0x30 ? mlx5_devcom_comp_set_ready+0x5/0x40 [mlx5_core] mlx5e_devcom_event_mpv+0x42/0x60 [mlx5_core] mlx5_devcom_send_event+0x8c/0x170 [mlx5_core] blocking_event+0x17b/0x230 [mlx5_core] notifier_call_chain+0x35/0xa0 blocking_notifier_call_chain+0x3d/0x60 mlx5_blocking_notifier_call_chain+0x22/0x30 [mlx5_core] mlx5_core_mp_event_replay+0x12/0x20 [mlx5_core] mlx5_ib_bind_slave_port+0x228/0x2c0 [mlx5_ib] mlx5_ib_stage_init_init+0x664/0x9d0 [mlx5_ib] ? idr_alloc_cyclic+0x50/0xb0 ? __kmalloc_cache_noprof+0x167/0x340 ? __kmalloc_noprof+0x1a7/0x430 __mlx5_ib_add+0x34/0xd0 [mlx5_ib] mlx5r_probe+0xe9/0x310 [mlx5_ib] ? kernfs_add_one+0x107/0x150 ? __mlx5_ib_add+0xd0/0xd0 [mlx5_ib] auxiliary_bus_probe+0x3e/0x90 really_probe+0xc5/0x3a0 ? driver_probe_device+0x90/0x90 __driver_probe_device+0x80/0x160 driver_probe_device+0x1e/0x90 __device_attach_driver+0x7d/0x100 bus_for_each_drv+0x80/0xd0 __device_attach+0xbc/0x1f0 bus_probe_device+0x86/0xa0 device_add+0x62d/0x830 __auxiliary_device_add+0x3b/0xa0 ? auxiliary_device_init+0x41/0x90 add_adev+0xd1/0x150 [mlx5_core] mlx5_rescan_drivers_locked+0x21c/0x300 [mlx5_core] esw_mode_change+0x6c/0xc0 [mlx5_core] mlx5_devlink_eswitch_mode_set+0x21e/0x640 [mlx5_core] devlink_nl_eswitch_set_doit+0x60/0xe0 genl_family_rcv_msg_doit+0xd0/0x120 genl_rcv_msg+0x180/0x2b0 ? devlink_get_from_attrs_lock+0x170/0x170 ? devlink_nl_eswitch_get_doit+0x290/0x290 ? devlink_nl_pre_doit_port_optional+0x50/0x50 ? genl_family_rcv_msg_dumpit+0xf0/0xf0 netlink_rcv_skb+0x54/0x100 genl_rcv+0x24/0x40 netlink_unicast+0x1fc/0x2d0 netlink_sendmsg+0x1e4/0x410 __sock_sendmsg+0x38/0x60 ? sockfd_lookup_light+0x12/0x60 __sys_sendto+0x105/0x160 ? __sys_recvmsg+0x4e/0x90 __x64_sys_sendto+0x20/0x30 do_syscall_64+0x4c/0x100 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f27bc91b13a Code: bb 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 8b 05 fa 96 2c 00 45 89 c9 4c 63 d1 48 63 ff 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff ---truncated---
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
A NULL pointer dereference in Linux kernel mlx5 IPsec cleanup on MPV devices crashes the system due to incorrect notifier unregister ordering.
Vulnerability
In the Linux kernel's net/mlx5 driver, the mlx5e_detach_netdev() function improperly orders cleanup operations for Multi-Port Virtual (MPV) devices when IPsec is in use. It disables blocking event notifiers before unregistering the devcom device, creating a race condition where the other device in the MPV setup may access a stale netdev pointer. This leads to a NULL pointer dereference in mlx5_devcom_comp_set_ready() during subsequent devcom events.
Exploitation
Exploitability requires the system to be running a vulnerable kernel with Mellanox ConnectX adapters configured in MPV mode and IPsec enabled. An attacker with local access or the ability to trigger device detachment (e.g., via devlink commands) can trigger the bug. No authentication is needed beyond local user privileges; however, the attacker must be able to initiate the device detachment sequence.
Impact
The crash manifests as a kernel NULL pointer dereference with a trace similar to the Oops shown in the description, leading to a system panic and denial of service. While the description does not confirm memory corruption beyond a crash, past similar bugs have been exploited for privilege escalation, though this CVE focuses on the availability impact.
Mitigation
The fix is included in Linux stable updates for kernels containing the vulnerable code (commits [1] and [2]). The patch ensures that the devcom device is unregistered and all pending operations complete before the event notifier is disabled. Systems should update to the latest stable kernel where this patch is backported.
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
2Patches
37e212cebc8638956686d398e664f76be38a1Vulnerability mechanics
Generated on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
3News mentions
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