7.5

CVE-2026-42493: x86 shadow paging is deprecated

Deferred
AliasesALPINE-CVE-2026-42493UBUNTU-CVE-2026-42493DEBIAN-CVE-2026-42493
Published 28-07-2026Last modified 28-07-2026

Vulnerability summary

CVE-2026-42493 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in xen. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 39.1% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (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
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.45%
0%100%
Low · -0.16 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 6 · Related 6
OPENSUSE-SU-2026:11441-1SUSE-SU-2026:3409-1SUSE-SU-2026:3423-1SUSE-SU-2026:3451-1SUSE-SU-2026:3462-1SUSE-SU-2026:4090-1

Timeline

  1. 28-07-2026
    PublishedVulnerability first disclosed.
  2. 28-07-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.45%

Chance of exploitation in the next 30 days

Percentile

39%

Versus all other CVEs

30-day change

Decrease -0.16 pp

From 0.61% on 04-10-2026

04-10-202603-11-2026

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-r0 | < 4.20.4-r0 | < 4.21.2-r0
Debian1 product
  • xen< 4.17.7-0+deb12u1 | < 4.20.3+127-gc42374a105-0+deb13u1 | < 4.20.3+127-gc42374a105-1
Ubuntu1 product
  • xenAll versions (No fix recorded)

3 vendors · 3 products

References

8 links