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Fencer Vulns
high 7.5

CVE-2026-42493 json

x86 shadow paging is deprecated

published 2026-07-28 3 mo ago modified 2026-07-28 3 mo ago also EUVD-2026-49770

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

Addressing certain issues, in particular related to operations which may take excessively long and therefore would need preemption, has turned out overly costly. Since alternatives (HVM/PVH: HAP, PV: shim) are commonly available, the decision was to deprecate the functionality, while still retaining it for people to use at their own (security) risk. Memory-wise small enough guests may still be okay to run.

Patch / fix

  • xen Debian 12 4.17.7-0+deb12u1
  • xen Debian 13 4.20.3+127-gc42374a105-0+deb13u1
  • xen Debian 14 4.20.3+127-gc42374a105-1

debian advisories DEBIAN-CVE-2026-42493

  • xen SLE Module for Server Applications 15 SP7, SLE Module for Basesystem 15 SP7 4.20.4_04-150700.3.46.1
  • xen SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +3 more 4.16.7_12-150400.4.89.3
  • xen SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 4.17.6_14-150500.3.76.3
  • xen SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 4.12.4_72-3.148.4
  • xen SLES for SAP 15 SP6, SLES 15 SP6-LTSS 4.18.5_20-150600.3.53.3

suse advisories SUSE-SU-2026:4090-1SUSE-SU-2026:3462-1SUSE-SU-2026:3451-1SUSE-SU-2026:3423-1SUSE-SU-2026:3409-1

  • xen openSUSE Tumbleweed 4.22.0_02-1.1

opensuse advisories openSUSE-SU-2026:11441-1

  • xen Alpine 3.21 4.19.6-r0
  • xen Alpine 3.23, Alpine 3.22 4.20.4-r0
  • xen Alpine 3.24 4.21.2-r0

alpine advisories ALPINE-CVE-2026-42493

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-42493 updated cvss 6.5

xen: Xen: Denial of Service due to prolonged x86 shadow paging operations

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Xen Xen

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.