CVE-2026-3842

Publication date 20 March 2026

Last updated 6 August 2026

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
qemu	26.04 LTS resolute	Vulnerable
	25.10 questing	Fixed 1:10.1.0+ds-5ubuntu2.6
	24.04 LTS noble	Fixed 1:8.2.2+ds-0ubuntu1.16
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
qemu	Upstream: 85af4e9

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.8 · High

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	High

Scores

Parameter	Value
Base score	7.8 · High
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

USN-8161-1
QEMU vulnerabilities
9 April 2026

Other references

https://www.cve.org/CVERecord?id=CVE-2026-3842