---
id: CVE-2026-79608
title: |-
  The workaround for XSA-433 (Zenbleed, CVE-2023-20593) was later
  re-worked to better integrate with other manipulations of the same MSR.
  In this rework an inverted conditional was introduced, resulting in the
  workaround to not be applied …
summary: |-
  The workaround for XSA-433 (Zenbleed, CVE-2023-20593) was later
  re-worked to better integrate with other manipulations of the same MSR.
  In this rework an inverted conditional was introduced, resulting in the
  workaround to not be applied …
severity: critical
published: '2026-10-13'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T16:10:14.750'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-79608'
references:
  - url: 'https://xenbits.xenproject.org/xsa/advisory-515.html'
    label: security@xen.org
  - url: 'http://xenbits.xen.org/xsa/advisory-515.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-13T16:35:46.744Z'
vendor: Xen
product: Xen
affected:
  - Xen
epss: 0.0035
epssPercentile: 0.28439
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-20T17:36:52.086871Z'
cvssSource: adp
---

## Overview

The workaround for XSA-433 (Zenbleed, CVE-2023-20593) was later
re-worked to better integrate with other manipulations of the same MSR.
In this rework an inverted conditional was introduced, resulting in the
workaround to not be applied when needed and vice versa.

For more details, see:
  http://xenbits.xen.org/xsa/advisory-433.html

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.