CVE-2026-42486

Pool-admin escalation via unrestricted hvm_serial setting

Published Jul 9, 2026 · Updated Jul 9, 2026

Privilege escalation in Xen Project XAPI all versions allows remote authenticated users with vm-admin access to write arbitrary dom0 files. XAPI permits vm-admin users to set VM.platform:hvm_serial without the pool-admin-only RBAC restriction, allowing its serial backend to target a dom0 file. Exploitation requires pool RBAC and a limited administrator account; successful use grants host-level file modification and pool-admin-equivalent control.

CVSS severity9.4
Critical
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Xen Project XAPI all versions allows remote authenticated users with vm-admin access to write arbitrary dom0 files. XAPI permits vm-admin users to set VM.platform:hvm_serial without the pool-admin-only RBAC restriction, allowing its serial backend to target a dom0 file. Exploitation requires pool RBAC and a limited administrator account; successful use grants host-level file modification and pool-admin-equivalent control.

The record

CVE
CVE-2026-42486
Published
Jul 9, 2026
Updated
Jul 9, 2026
Vendor
Xen Project
Product
XAPI
Classifications
CWE-250, CAPEC-233, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=all

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Xen Project · XAPIversion=all

Published CVSS scores

9.4Xen ProjectCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-250Execution with Unnecessary Privileges
CAPEC-233Privilege Escalation
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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