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Linux Kernel EUVD-2026-27598

| CVE-2026-43094 MEDIUM
NULL Pointer Dereference (CWE-476)
2026-05-06 Linux GHSA-8c3v-5v6w-588p
5.5
CVSS 3.1
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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

3
Analysis Generated
May 19, 2026 - 23:01 vuln.today
CVSS changed
May 19, 2026 - 20:52 NVD
5.5 (MEDIUM)
Patch available
May 06, 2026 - 11:31 EUVD

DescriptionNVD

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

ixgbevf: add missing negotiate_features op to Hyper-V ops table

Commit a7075f501bd3 ("ixgbevf: fix mailbox API compatibility by negotiating supported features") added the .negotiate_features callback to ixgbe_mac_operations and populated it in ixgbevf_mac_ops, but forgot to add it to ixgbevf_hv_mac_ops. This leaves the function pointer NULL on Hyper-V VMs.

During probe, ixgbevf_negotiate_api() calls ixgbevf_set_features(), which unconditionally dereferences hw->mac.ops.negotiate_features(). On Hyper-V this results in a NULL pointer dereference:

BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine [...] Workqueue: events work_for_cpu_fn RIP: 0010:0x0 [...] Call Trace: ixgbevf_negotiate_api+0x66/0x160 [ixgbevf] ixgbevf_sw_init+0xe4/0x1f0 [ixgbevf] ixgbevf_probe+0x20f/0x4a0 [ixgbevf] local_pci_probe+0x50/0xa0 work_for_cpu_fn+0x1a/0x30 [...]

Add ixgbevf_hv_negotiate_features_vf() that returns -EOPNOTSUPP and wire it into ixgbevf_hv_mac_ops. The caller already handles -EOPNOTSUPP gracefully.

AnalysisAI

NULL pointer dereference in the Linux kernel ixgbevf driver crashes Hyper-V guest VMs during device probe, causing a kernel panic and complete denial of service. The regression was introduced when commit a7075f501bd3 added a .negotiate_features callback to ixgbe_mac_operations and populated it for the standard ops table (ixgbevf_mac_ops) but omitted it from the Hyper-V-specific table (ixgbevf_hv_mac_ops), leaving that pointer NULL on Hyper-V guests. …

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EUVD-2026-27598 vulnerability details – vuln.today

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