Published Jun 24, 2026Sources checked Nov 13, 2026
5.5MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-53015 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: Nov 5, 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-2026-53015?
In the Linux kernel, the following vulnerability has been resolved:
erofs: unify lcn as u64 for 32-bit platforms
As sashiko reported [1], `lcn` was typed as `unsigned long` (or `unsigned int` sometimes), which is only 32 bits wide on 32-bit platforms, which causes `(lcn << lclusterbits)` to be truncated at 4 GiB.
In order to consolidate the logic, just use `u64` consistently around the codebase.