Published Apr 22, 2026Sources checked Nov 12, 2026
7.8HIGHCVSS out of 10
What this means
Review the available evidence
CVE-2026-31447 and is rated High severity with a CVSS score of 7.8. 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: Apr 29, 2026
CBL-Mariner Releases
Vendor-listed releases
6.6.134.1-2
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-2026-31447?
In the Linux kernel, the following vulnerability has been resolved:
ext4: reject mount if bigalloc with s_first_data_block != 0
bigalloc with s_first_data_block != 0 is not supported, reject mounting it.