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EUVDEUVD-2026-42604

| CVE-2026-23561 CRITICAL
Execution with Unnecessary Privileges (CWE-250)
2026-05-08 GHSA-35jv-46p3-x4g4
Privilege Escalation
Critical
Disputed · 9.4 Vendor
View

Vulnerability Assessment

Weakness
CWE
CWE-250
ASVS 5.0
V8 - Authorization Unnecessary privilege execution
Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 09, 2026

Local privilege escalation in the Xen hypervisor, disclosed as one of five issues under Xen Security Advisory XSA-489 (alongside CVE-2026-23559/23560/23562/42486), lets a malicious or compromised guest run code with more privilege than intended and cross the guest/host trust boundary. The CVSS 4.0 vector (AV:L, scope-changed with high confidentiality, integrity and availability impact to subsequent systems) indicates a guest can affect the underlying host and other guests, consistent with the CWE-250 'execution with unnecessary privileges' root cause. No public exploit identified at time of analysis, and it is not listed in CISA KEV.

Affected VersionsENISA

Xapi all

Affects your stack

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  • Exploit and PoC references, threat intelligence from 22 sources
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Severity by source

Sources disagree (Medium–Critical)
Vendor (CNA) PRIMARY 9.4 CRITICAL
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
SUSE MEDIUM

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorVendor

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
High
Subsequent system: Integrity
High
Subsequent system: Availability
High

Lifecycle Timeline

2
CVSS changed
Jul 09, 2026 - 16:22 NVD
9.4 (CRITICAL)
CVE Published
May 08, 2026 - 06:45 nvd
UNKNOWN (no severity yet)

Description PRE-NVD

Disclosed via oss-security. NVD scoring and full description are pending.

Executive ViewAI

Why It Matters

A critical local privilege escalation vulnerability (CVE-2026-23561, CVSS 9.4) in Xen hypervisor enables guest virtual machines to escalate privileges and compromise the host system and other tenant workloads. Organizations running Xen-based cloud infrastructure face loss of guest-to-host isolation-the foundational security boundary protecting workload separation.

Recommended Action

24 hours: Inventory all Xen deployments and determine affected versions from XSA-489 advisory; restrict new guest VM provisioning from untrusted sources. 7 days: Deploy enhanced hypervisor monitoring for suspicious guest behavior; review guest VM isolation profiles and apply strict least-privilege access controls. 30 days: Monitor Xen security advisories for patch release; maintain staged deployment plan for immediate patching when available.

Business Impact: Severe
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: restrict guest management and provisioning capabilities to trusted administrators only; segregate critical workloads onto dedicated, isolated Xen hosts; implement hypervisor-level activity monitoring for anomalous guest system calls; apply hardened guest OS configurations (SELinux, AppArmor) to limit local privilege escalation feasibility.

Threat Intelligence Overview

EPSS Score
0.1%
Top 96% exploitable
Social Media
5
Sightings
Data Quality
5 sources
Confidence: Medium
EUVD NVD CVE.org EPSS Vendor CIRCL

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact
Very High

Priority Score

47
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +47
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Privilege Escalation HIGH

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.

Same weakness CWE-250 – Execution with Unnecessary Privileges

View all
CVE-2023-52030 CRITICAL POC
9.8
CVE-2025-57119 CRITICAL POC
9.8
CVE-2024-25421 CRITICAL POC
9.8
CVE-2023-46360 HIGH POC
8.8
CVE-2024-6913 CRITICAL POC
9.3
CVE-2026-92574 HIGH POC
8.8
CVE-2022-1808 HIGH POC
8.8
CVE-2022-0071 HIGH POC
8.8

Same technique Privilege Escalation

View all
CVE-2024-0012 CRITICAL POC
9.3
CVE-2025-47812 CRITICAL POC
10.0
CVE-2013-0422 CRITICAL POC
9.8
CVE-2013-0632 CRITICAL POC
9.8
CVE-2024-9474 MEDIUM POC
6.9
CVE-2017-5689 CRITICAL POC
9.8
CVE-2021-20021 CRITICAL POC
9.8
CVE-2017-12635 CRITICAL POC
9.8

Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Performance Computing 15 SP7 Affected
SUSE Linux Enterprise Micro 5.3 Affected
SUSE Linux Enterprise Micro 5.4 Affected
SUSE Linux Enterprise Micro 5.5 Affected

References

Advisories & patches
ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-23561 ADVISORY https://www.openwall.com/lists/oss-security/2026/04/29 REF https://xenbits.xen.org/xsa/advisory-489.html

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