CVE intelligence

CVE-2026-3842

Vulnerability intelligence

Published Jul 16, 2026Sources checked Oct 28, 2026

7.8HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-3842 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: Jul 21, 2026

CBL-Mariner Releases

Vendor-listed releases

9.1.0-11

CISA KEVNot listedBased on the latest collected catalog

EPSS0.2%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-3842?

A flaw was found in QEMU. This vulnerability allows a local attacker within a guest virtual machine to write data beyond its allocated memory.

This occurs when cpu_physical_memory_map() returns a shorter length than expected, leading to an out-of-bounds write. Successful exploitation could result in unauthorized access to guest memory or corruption of heap-allocated objects, potentially causing information disclosure, data integrity issues, or a denial of service.

Source: NVD