Published Jul 19, 2026Sources checked Oct 28, 2026
5.5MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-63999 and is rated Medium severity with a CVSS score of 5.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: Sep 24, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSS0.1%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-63999?
In the Linux kernel, the following vulnerability has been resolved:
ethtool: rss: fix indir_table and hkey leak on get_rxfh failure
rss_prepare_get() allocates the indirection table and hash key buffer via rss_get_data_alloc(), then calls ops->get_rxfh() to populate them. If get_rxfh() fails, the function returns an error without freeing the allocation.