9.8

CVE-2026-79608: x86/AMD: ineffectual Zenbleed workaround

Awaiting analysis
AliasesALPINE-CVE-2026-79608DEBIAN-CVE-2026-79608UBUNTU-CVE-2026-79608
Published 13-10-2026Last modified 20-10-2026

Vulnerability summary

CVE-2026-79608 is a critical (CVSS 9.8) vulnerability in xen. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 27.1% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.8 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.34%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:12138-1SUSE-SU-2026:4942-1

Timeline

  1. 13-10-2026
    PublishedVulnerability first disclosed.
  2. 20-10-2026
    Last modifiedVulnerability information updated.

Description

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

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.34%

Chance of exploitation in the next 30 days

Percentile

27%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

14-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Alpine1 product
  • xen< 4.19.6-r2 | < 4.20.4-r2 | < 4.21.2-r2
Debian1 product
  • xenAll versions (No fix recorded) | < 4.20.4+39-gf1e1321c87-0+deb13u1 | < 4.20.4+39-gf1e1321c87-1
Ubuntu1 product
  • xenAll versions (No fix recorded)

3 vendors · 3 products

References

7 links