Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: ethtool: coalesce: cap profile updates at NET_DIM_PARAMS_NUM_PROFILES… (CVE-2026-63987)

The vulnerability in the Linux kernel's ethtool coalesce feature involves the ethnl_update_profile() function walking the ETHTOOL_A_PROFILE_IRQ_MODERATION nested list with an index 'i' that is incremented and used to write new_profile[i++] without proper bounds checking. The destination buffer is allocated with NET_DIM_PARAMS_NUM_PROFILES entries (5), but the Netlink nested attribute count is fully user-controlled and not constrained by Netlink policies. This can cause out-of-bounds writes leading to potential corruption or escalation. The issue affects numerous specific Linux kernel versions, and a patch has been released to fix this by capping profile updates at NET_DIM_PARAMS_NUM_PROFILES.

The vulnerability allows a local attacker to cause out-of-bounds writes in kernel memory due to unchecked user-controlled Netlink nested attributes, potentially leading to system instability, privilege escalation, or denial of service. The CVSS score of 7.8 reflects high impact on confidentiality, integrity, and availability. There are no known exploits in the wild at this time.

A vendor-provided patch is available and should be applied to affected Linux kernel versions to resolve this vulnerability. The vendor advisory confirms the issue has been fixed. Users should update their Linux kernel to a version including this fix. No additional mitigations are specified or required beyond applying the official patch.