CVE intelligence

CVE-2026-34743

Vulnerability intelligence

Published Apr 2, 2026Sources checked Nov 11, 2026

5.3MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-34743 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: Sep 25, 2026

Vendor remediation details

CBL-Mariner Releases Release Notes

Vendor-listed releases

5.4.4-3
5.2.5-2
1.75.0-28
1.72.0-16
1.90.0-7

CISA KEVNot listedBased on the latest collected catalog

EPSS0.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-34743?

XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzma_index_decoder() was used to decode an Index that contained no Records, the resulting lzma_index was left in a state where where a subsequent lzma_index_append() would allocate too little memory, and a buffer overflow would occur.

This issue has been patched in version 5.8.3.

Source: NVD