SB20260815336 - Use-after-free in Linux kernel meta fbnic driver

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-72393)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a use-after-free in fbnic_tx_lso in the fbnic transmit offload path when processing a specially crafted GSO skb that triggers skb reallocation. A local user can send crafted traffic to trigger the stale shared-info pointer dereference to cause a denial of service.

The issue occurs because skb_cow_head() may reallocate the skb and its shared info before the cached pointer is reused.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/21f304c2aae46625e050c28d979f4b9d83faa85e
• https://git.kernel.org/stable/c/62b68b774f06bf52e329f254f0199bc43d350ccf
• https://git.kernel.org/stable/c/83df3e2594cd78aa40b1246a19879abb4891945b