Published Nov 15, 2021Sources checked Nov 11, 2026
5.3MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2021-42374 and is rated Medium severity with a CVSS score of 5.3. 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: Aug 17, 2026
CBL-Mariner Releases
Vendor-listed releases
1.34.1-1
1.35.0-1
1.35.1-1
CISA KEVNot listedBased on the latest collected catalog
EPSS0.6%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2021-42374?
An out-of-bounds heap read in Busybox's unlzma applet leads to information leak and denial of service when crafted LZMA-compressed input is decompressed. This can be triggered by any applet/format that