Junglewise Threat Intelligence

CVE-2025-39968: Linux Kernel i40e resource exhaustion in VF cloud filters

CVE-2025-39968 · Severity: high · CVSS 7.3 · 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 user within a virtual machine to exhaust system resources. By requesting an unlimited number of network filters, a guest system could potentially cause a denial-of-service condition on the host server. This affects environments using Intel Ethernet 700 Series controllers with Virtual Functions enabled.

Technical details

A vulnerability in the i40e driver's Virtual Function (VF) interface allows a guest VM to request an arbitrary number of cloud filters. The function `i40e_vc_add_cloud_filter` in `drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c` failed to validate the `num_cloud_filters` count against a maximum threshold. A local attacker with privileges to manage VF interfaces can exploit this to consume excessive kernel memory or hardware resources, leading to a Denial of Service (DoS). The fix introduces a hard limit of 0xFF00 (65280) filters per VF.

Affected products

  • Linux Linux Kernel 4.17 to 6.11.x (fixed in 5.4.300, 5.10.245, 5.15.194, and others)

Timeline

  • 2025-08-13: other: Patch authored by Intel
  • 2025-10-02: patched: Patch committed to stable tree
  • 2025-10-15: disclosed: CVE published

References

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