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

net/mlx5: Fix switchdev mode rollback in case of failure

If for some internal reason switchdev mode fails, we rollback to legacy
mode, before this patch, rollback will unregister the uplink netdev and
leave it unregistered causing the below kernel bug.

To fix this, we need to avoid netdev unregister by setting the proper
rollback flag 'MLX5_PRIV_FLAGS_SWITCH_LEGACY' to indicate legacy mode.

devlink (431) used greatest stack depth: 11048 bytes left
mlx5_core 0000:00:03.0: E-Switch: Disable: mode(LEGACY), nvfs(0), \
necvfs(0), active vports(0)
mlx5_core 0000:00:03.0: E-Switch: Supported tc chains and prios offload
mlx5_core 0000:00:03.0: Loading uplink representor for vport 65535
mlx5_core 0000:00:03.0: mlx5_cmd_out_err:816:(pid 456): \
QUERY_HCA_CAP(0x100) op_mod(0x0) failed, \
status bad parameter(0x3), syndrome (0x3a3846), err(-22)
mlx5_core 0000:00:03.0 enp0s3np0 (unregistered): Unloading uplink \
representor for vport 65535
------------[ cut here ]------------
kernel BUG at net/core/dev.c:12070!
Oops: invalid opcode: 0000 [#1] SMP NOPTI
CPU: 2 UID: 0 PID: 456 Comm: devlink Not tainted 6.16.0-rc3+ \
#9 PREEMPT(voluntary)
RIP: 0010:unregister_netdevice_many_notify+0x123/0xae0
...
Call Trace:
[ 90.923094] unregister_netdevice_queue+0xad/0xf0
[ 90.923323] unregister_netdev+0x1c/0x40
[ 90.923522] mlx5e_vport_rep_unload+0x61/0xc6
[ 90.923736] esw_offloads_enable+0x8e6/0x920
[ 90.923947] mlx5_eswitch_enable_locked+0x349/0x430
[ 90.924182] ? is_mp_supported+0x57/0xb0
[ 90.924376] mlx5_devlink_eswitch_mode_set+0x167/0x350
[ 90.924628] devlink_nl_eswitch_set_doit+0x6f/0xf0
[ 90.924862] genl_family_rcv_msg_doit+0xe8/0x140
[ 90.925088] genl_rcv_msg+0x18b/0x290
[ 90.925269] ? __pfx_devlink_nl_pre_doit+0x10/0x10
[ 90.925506] ? __pfx_devlink_nl_eswitch_set_doit+0x10/0x10
[ 90.925766] ? __pfx_devlink_nl_post_doit+0x10/0x10
[ 90.926001] ? __pfx_genl_rcv_msg+0x10/0x10
[ 90.926206] netlink_rcv_skb+0x52/0x100
[ 90.926393] genl_rcv+0x28/0x40
[ 90.926557] netlink_unicast+0x27d/0x3d0
[ 90.926749] netlink_sendmsg+0x1f7/0x430
[ 90.926942] __sys_sendto+0x213/0x220
[ 90.927127] ? __sys_recvmsg+0x6a/0xd0
[ 90.927312] __x64_sys_sendto+0x24/0x30
[ 90.927504] do_syscall_64+0x50/0x1c0
[ 90.927687] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 90.927929] RIP: 0033:0x7f7d0363e047
Published: 2026-05-01
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability arises when the Linux kernel attempts to roll back from switchdev mode to legacy mode due to a failure. During this rollback, an unregistration of the uplink network device occurs, leaving the device in an unregistered state. This triggers a kernel BUG at dev.c, resulting in a kernel panic and loss of service. The fault does not provide an attacker with a direct code execution or privilege escalation path; the impact is primarily failure of the network stack and the entire system. The weakness falls under improper resource cleanup in kernel code.

Affected Systems

All Linux kernel distributions that include the mlx5 network driver and support the eswitch devlink interface are potentially affected. The issue may manifest when the operating system runs drivers that provide switchdev or eswitch functionality for Mellanox NICs. Affected kernels are those prior to the commit that added the rollback flag 'MLX5_PRIV_FLAGS_SWITCH_LEGACY', typically before kernel 6.17. No specific vendor or product release numbers are listed, so any kernel build the standard Linux source that includes the mlx5 driver and switchdev code is in scope.

Risk and Exploitability

The CVSS score is 5.5 and EPSS score is 0.00023 (< 1%), so the quantified risk measure indicates moderate severity. The bug causes a kernel panic, a denial‑of‑service condition that can be triggered by administrative devlink or network configuration commands that attempt to enable or disable eswitch mode. Because the exploit requires knowledge of the device and initiates a kernel‑level command, it is likely limited to a local or privileged user. Nevertheless, the potential for service interruption warrants immediate patching. The vulnerability is not listed in the CISA KEV catalog, implying there is no publicly known exploit at the time of release. Because the failure occurs during a controlled rollback, a legitimate system administration action could inadvertently trigger it, so the risk is operationally significant for users of Mellanox switches with switchdev support.

Generated by OpenCVE AI on May 7, 2026 at 22:07 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply a kernel update that incorporates the fix for the mlx5 switchdev rollback bug.
  • Disable switchdev mode in the system configuration (e.g., via devlink) or set it to legacy mode to eliminate the rollback path.
  • Reboot the system or reload the mlx5 driver to ensure the new configuration takes effect and to verify stability in production.

Generated by OpenCVE AI on May 7, 2026 at 22:07 UTC.

Tracking

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Advisories

No advisories yet.

History

Thu, 07 May 2026 20:30:00 +0000

Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:6.13:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.13:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.13:rc7:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*

Sat, 02 May 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-372
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Fri, 01 May 2026 14:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix switchdev mode rollback in case of failure If for some internal reason switchdev mode fails, we rollback to legacy mode, before this patch, rollback will unregister the uplink netdev and leave it unregistered causing the below kernel bug. To fix this, we need to avoid netdev unregister by setting the proper rollback flag 'MLX5_PRIV_FLAGS_SWITCH_LEGACY' to indicate legacy mode. devlink (431) used greatest stack depth: 11048 bytes left mlx5_core 0000:00:03.0: E-Switch: Disable: mode(LEGACY), nvfs(0), \ necvfs(0), active vports(0) mlx5_core 0000:00:03.0: E-Switch: Supported tc chains and prios offload mlx5_core 0000:00:03.0: Loading uplink representor for vport 65535 mlx5_core 0000:00:03.0: mlx5_cmd_out_err:816:(pid 456): \ QUERY_HCA_CAP(0x100) op_mod(0x0) failed, \ status bad parameter(0x3), syndrome (0x3a3846), err(-22) mlx5_core 0000:00:03.0 enp0s3np0 (unregistered): Unloading uplink \ representor for vport 65535 ------------[ cut here ]------------ kernel BUG at net/core/dev.c:12070! Oops: invalid opcode: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 456 Comm: devlink Not tainted 6.16.0-rc3+ \ #9 PREEMPT(voluntary) RIP: 0010:unregister_netdevice_many_notify+0x123/0xae0 ... Call Trace: [ 90.923094] unregister_netdevice_queue+0xad/0xf0 [ 90.923323] unregister_netdev+0x1c/0x40 [ 90.923522] mlx5e_vport_rep_unload+0x61/0xc6 [ 90.923736] esw_offloads_enable+0x8e6/0x920 [ 90.923947] mlx5_eswitch_enable_locked+0x349/0x430 [ 90.924182] ? is_mp_supported+0x57/0xb0 [ 90.924376] mlx5_devlink_eswitch_mode_set+0x167/0x350 [ 90.924628] devlink_nl_eswitch_set_doit+0x6f/0xf0 [ 90.924862] genl_family_rcv_msg_doit+0xe8/0x140 [ 90.925088] genl_rcv_msg+0x18b/0x290 [ 90.925269] ? __pfx_devlink_nl_pre_doit+0x10/0x10 [ 90.925506] ? __pfx_devlink_nl_eswitch_set_doit+0x10/0x10 [ 90.925766] ? __pfx_devlink_nl_post_doit+0x10/0x10 [ 90.926001] ? __pfx_genl_rcv_msg+0x10/0x10 [ 90.926206] netlink_rcv_skb+0x52/0x100 [ 90.926393] genl_rcv+0x28/0x40 [ 90.926557] netlink_unicast+0x27d/0x3d0 [ 90.926749] netlink_sendmsg+0x1f7/0x430 [ 90.926942] __sys_sendto+0x213/0x220 [ 90.927127] ? __sys_recvmsg+0x6a/0xd0 [ 90.927312] __x64_sys_sendto+0x24/0x30 [ 90.927504] do_syscall_64+0x50/0x1c0 [ 90.927687] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 90.927929] RIP: 0033:0x7f7d0363e047
Title net/mlx5: Fix switchdev mode rollback in case of failure
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-23T16:05:57.203Z

Reserved: 2026-05-01T14:12:55.974Z

Link: CVE-2026-43012

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2026-05-01T15:16:45.117

Modified: 2026-05-07T20:28:15.953

Link: CVE-2026-43012

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-05-01T00:00:00Z

Links: CVE-2026-43012 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-07T22:15:06Z

Weaknesses