Junglewise Threat Intelligence

CVE-2025-39969: Linux Kernel i40e improper state validation in VF resource management

CVE-2025-39969 · Severity: high · CVSS 8.8 · Published 2025-10-15

Technologies: Linux Kernel. Vendors: Linux.

Executive brief

A vulnerability in the Linux kernel's Intel i40e network driver could allow a local attacker to cause a system crash or potentially gain unauthorized access to system resources. The issue stems from how the driver manages Virtual Functions (VFs), which are used to share a single physical network connection among multiple virtual environments. An exploit could lead to a complete compromise of the host system's availability and data integrity.

Technical details

A vulnerability was identified in the i40e network driver within the Linux kernel's Virtual Function (VF) management logic. The driver incorrectly relied on the I40E_VF_STATE_ACTIVE flag to determine if a VF was permitted to obtain resources, failing to account for other valid active states. This logic error is resolved by introducing and checking the I40E_VF_STATE_RESOURCES_LOADED flag in i40e_vc_get_vf_resources_msg() and ensuring it is cleared during resets. A local attacker with low privileges could exploit this state inconsistency to trigger kernel-level errors or bypass resource isolation boundaries. Patches have been released across multiple stable kernel branches.

Affected products

  • Linux Linux Kernel 5.4.165 to 5.4.300, 5.10.85 to 5.10.245, 5.15.8 to 5.15.194, 5.16 and later

Timeline

  • 2025-09-29: other: Patch authored
  • 2025-10-15: advisory: CVE published

References

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