Detections
Analytics

Xen: x86 Mismatched Mapcache Metadata (XSA-494)

high Nessus Plugin ID 320867

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Synopsis

The remote Xen hypervisor installation is missing a security update.

Description

Some shadow paging errors paths will switch the page-tables without updating the currently running vCPU reference.
This causes a mismatch between the loaded page-tables and the mapcache metadata which can lead to corruption of the mapcache. This can result in privilege escalation, Denial of Service (DoS) affecting the entire host, and information leaks.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Apply the appropriate patch according to the vendor advisory.

See Also

https://xenbits.xenproject.org/xsa/advisory-494.html

Plugin Details

Severity: High

ID: 320867

File Name: xen_server_XSA-494.nasl

Version: 1.4

Type: Local

Family: Misc.

Published: 6/12/2026

Updated: 6/22/2026

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.96

CVSS v2

Risk Factor: Medium

Base Score: 6

Temporal Score: 4.4

Vector: CVSS2#AV:L/AC:H/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2026-42488

CVSS v3

Risk Factor: High

Base Score: 8.1

Temporal Score: 7.1

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:xen:xen

Required KB Items: Settings/ParanoidReport, installed_sw/Xen Hypervisor

Exploit Ease: No known exploits are available

Patch Publication Date: 6/9/2026

Vulnerability Publication Date: 6/9/2026

Reference Information

CVE: CVE-2026-42488

IAVB: 2026-B-0069, 2026-B-0151