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Linux Kernel mlx5 CVE-2026-43467

| EUVDEUVD-2026-28773 MEDIUM
2026-05-08 Linux GHSA-5qcc-ffcx-c8mp
Linux Denial Of Service Red Hat Suse
5.5
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
SUSE
MEDIUM
qualitative
Red Hat
5.5 MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

4
Analysis Generated
May 21, 2026 - 15:38 vuln.today
CVSS changed
May 21, 2026 - 15:37 NVD
5.5 (MEDIUM)
Patch available
May 08, 2026 - 16:18 EUVD
CVE Published
May 08, 2026 - 14:22 nvd
UNKNOWN (no severity yet)

DescriptionCVE.org

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

net/mlx5: Fix crash when moving to switchdev mode

When moving to switchdev mode when the device doesn't support IPsec, we try to clean up the IPsec resources anyway which causes the crash below, fix that by correctly checking for IPsec support before trying to clean up its resources.

[27642.515799] WARNING: arch/x86/mm/fault.c:1276 at do_user_addr_fault+0x18a/0x680, CPU#4: devlink/6490 [27642.517159] Modules linked in: xt_conntrack xt_MASQUERADE ip6table_nat ip6table_filter ip6_tables iptable_nat nf_nat xt_addrtype rpcsec_gss_krb5 auth_rpcgss oid_registry overlay mlx5_fwctl nfnetlink zram zsmalloc mlx5_ib fuse rpcrdma rdma_ucm ib_uverbs ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_core ib_core [27642.521358] CPU: 4 UID: 0 PID: 6490 Comm: devlink Not tainted 6.19.0-rc5_for_upstream_min_debug_2026_01_14_16_47 #1 NONE [27642.522923] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [27642.524528] RIP: 0010:do_user_addr_fault+0x18a/0x680 [27642.525362] Code: ff 0f 84 75 03 00 00 48 89 ee 4c 89 e7 e8 5e b9 22 00 49 89 c0 48 85 c0 0f 84 a8 02 00 00 f7 c3 60 80 00 00 74 22 31 c9 eb ae <0f> 0b 48 83 c4 10 48 89 ea 48 89 de 4c 89 f7 5b 5d 41 5c 41 5d 41 [27642.528166] RSP: 0018:ffff88810770f6b8 EFLAGS: 00010046 [27642.529038] RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffff88810b980f00 [27642.530158] RDX: 00000000000000a0 RSI: 0000000000000002 RDI: ffff88810770f728 [27642.531270] RBP: 00000000000000a0 R08: 0000000000000000 R09: 0000000000000000 [27642.532383] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888103f3c4c0 [27642.533499] R13: 0000000000000000 R14: ffff88810770f728 R15: 0000000000000000 [27642.534614] FS: 00007f197c741740(0000) GS:ffff88856a94c000(0000) knlGS:0000000000000000 [27642.535915] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [27642.536858] CR2: 00000000000000a0 CR3: 000000011334c003 CR4: 0000000000172eb0 [27642.537982] Call Trace: [27642.538466] <TASK> [27642.538907] exc_page_fault+0x76/0x140 [27642.539583] asm_exc_page_fault+0x22/0x30 [27642.540282] RIP: 0010:_raw_spin_lock_irqsave+0x10/0x30 [27642.541134] Code: 07 85 c0 75 11 ba ff 00 00 00 f0 0f b1 17 75 06 b8 01 00 00 00 c3 31 c0 c3 90 0f 1f 44 00 00 53 9c 5b fa 31 c0 ba 01 00 00 00 <f0> 0f b1 17 75 05 48 89 d8 5b c3 89 c6 e8 7e 02 00 00 48 89 d8 5b [27642.543936] RSP: 0018:ffff88810770f7d8 EFLAGS: 00010046 [27642.544803] RAX: 0000000000000000 RBX: 0000000000000202 RCX: ffff888113ad96d8 [27642.545916] RDX: 0000000000000001 RSI: ffff88810770f818 RDI: 00000000000000a0 [27642.547027] RBP: 0000000000000098 R08: 0000000000000400 R09: ffff88810b980f00 [27642.548140] R10: 0000000000000001 R11: ffff888101845a80 R12: 00000000000000a8 [27642.549263] R13: ffffffffa02a9060 R14: 00000000000000a0 R15: ffff8881130d8a40 [27642.550379] complete_all+0x20/0x90 [27642.551010] mlx5e_ipsec_disable_events+0xb6/0xf0 [mlx5_core] [27642.552022] mlx5e_nic_disable+0x12d/0x220 [mlx5_core] [27642.552929] mlx5e_detach_netdev+0x66/0xf0 [mlx5_core] [27642.553822] mlx5e_netdev_change_profile+0x5b/0x120 [mlx5_core] [27642.554821] mlx5e_vport_rep_load+0x419/0x590 [mlx5_core] [27642.555757] ? xa_load+0x53/0x90 [27642.556361] __esw_offloads_load_rep+0x54/0x70 [mlx5_core] [27642.557328] mlx5_esw_offloads_rep_load+0x45/0xd0 [mlx5_core] [27642.558320] esw_offloads_enable+0xb4b/0xc90 [mlx5_core] [27642.559247] mlx5_eswitch_enable_locked+0x34e/0x4f0 [mlx5_core] [27642.560257] ? mlx5_rescan_drivers_locked+0x222/0x2d0 [mlx5_core] [27642.561284] mlx5_devlink_eswitch_mode_set+0x5ac/0x9c0 [mlx5_core] [27642.562334] ? devlink_rate_set_ops_supported+0x21/0x3a0 [27642.563220] devlink_nl_eswitch_set_doit+0x67/0xe0 [27642.564026] genl_family_rcv_msg_doit+0xe0/0x130 [27642.564816] genl_rcv_msg+0x183/0x290 [27642.565466] ? __devlink_nl_pre_doit.isra.0+0x160/0x160 [27642.566329] ? d ---truncated---

AnalysisAI

Kernel denial-of-service in the mlx5_core driver (Mellanox/NVIDIA ConnectX) occurs when a privileged local user switches the eswitch to switchdev mode on hardware that does not support IPsec offload. The driver unconditionally invokes IPsec resource cleanup via mlx5e_ipsec_disable_events regardless of hardware capability, dereferencing a null or uninitialized pointer at offset 0xa0 and triggering a kernel page fault that crashes the system. No public exploit identified at time of analysis; EPSS of 0.02% (5th percentile) and no CISA KEV listing indicate negligible real-world exploitation activity.

Technical ContextAI

The mlx5_core module is the Linux kernel driver for Mellanox/NVIDIA ConnectX SmartNIC and Ethernet adapters, which expose an embedded switch (eswitch) configurable via the devlink interface. The eswitch supports two modes - legacy and switchdev (used for SR-IOV hardware offload). The transition to switchdev mode triggers a NIC profile change, calling mlx5e_nic_disable as part of teardown. Within that path, mlx5e_ipsec_disable_events is called unconditionally to flush IPsec event completions. On hardware without IPsec support, the relevant IPsec data structure is NULL or never initialized; the function then calls complete_all on a spinlock embedded at offset 0xa0 of that null pointer, producing a page fault (CR2: 0x00000000000000a0) inside _raw_spin_lock_irqsave. The root cause is a missing capability or feature-presence check before entering the IPsec cleanup code path. While no formal CWE is assigned, this is consistent with CWE-476 (NULL Pointer Dereference) or CWE-754 (Improper Check for Unusual or Exceptional Conditions). The full crash call chain is confirmed in the kernel stack trace: devlink_nl_eswitch_set_doit → mlx5_devlink_eswitch_mode_set → esw_offloads_enable → mlx5e_vport_rep_load → mlx5e_netdev_change_profile → mlx5e_detach_netdev → mlx5e_nic_disable → mlx5e_ipsec_disable_events. Affected CPE: cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*.

RemediationAI

The primary remediation is to upgrade to a patched kernel version: Linux 6.12.78, 6.18.19, or 6.19.9, all of which include the fix that gates IPsec cleanup behind a hardware capability check. The upstream fix commits are linked from the kernel stable tree at https://git.kernel.org/stable/c/05c9a6df3646cdd25e0e10e6ef2d20cdba3ed8f9 and its backport siblings. For environments where immediate kernel upgrade is not feasible, restrict access to CAP_NET_ADMIN - specifically prevent unprivileged processes and non-root containers from invoking devlink eswitch mode transitions. This can be enforced via SELinux policy (denying the net_admin capability for untrusted domains), AppArmor profiles, or seccomp filters targeting devlink netlink socket operations. Note that restricting CAP_NET_ADMIN more broadly may impact SR-IOV VF management, DPDK workflows, or other legitimate administrative tooling that depends on network capability delegation. A targeted AppArmor or SELinux rule scoped to the specific devlink operation is preferable to a blanket capability removal. No workaround eliminates the root cause - patching is the only definitive fix.

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Vendor StatusVendor

SUSE

Severity: Medium
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise High Availability Extension 15 SP7 Fixed
SUSE Linux Enterprise High Availability Extension 15 SP7 Fixed
SUSE Linux Enterprise High Performance Computing 15 SP7 Fixed

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CVE-2026-43467 vulnerability details – vuln.today
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