by Kastro
Paper/Archive/CVE-2026-79608

CVE-2026-79608

Xen Xen — x86/AMD: ineffectual Zenbleed workaround

EPSS 0.4%CVSS 9.8
critical.is priorityof 100
35
CVSS 9.8 (ADP)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 28.6.286 × 205.7No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

Affected

ProductAffectedFixed inSource
Xensee advisory–CNA

Scores by source

CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refxenbits.xenproject.org/xsa/advisory-515.htmlrefxenbits.xen.org/xsa/advisory-515.html