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Red Hat Enterprise Linux 10 EUVDEUVD-2026-17111

| CVE-2026-5164 MEDIUM
Classic Buffer Overflow (CWE-120)
2026-03-30 redhat GHSA-6457-73j6-h3qg
6.7
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Buffer copy size validation
MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS 6.7 is moderately elevated but the real-world risk is constrained by authentication and privilege requirements. The CVSS vector shows AV:L (local attack only), AC:L (low complexity), and critically PR:H (requires high-privilege user), which substantially reduces exploitability in multi-tenant or least-privilege environments. EPSS data is not provided, but the combination of local-only attack vector and high-privilege requirement suggests lower exploitation probability than a remote or low-privilege vulnerability despite the buffer overflow nature. No KEV status is indicated, implying no confirmed active exploitation at time of analysis. The existence of a GitHub PR fix (reference [3]) indicates the vulnerability was reported through responsible disclosure. Primary risk applies to systems where unprivileged users can be compromised or where high-privilege user accounts are less tightly controlled. The DoS-only impact (no code execution despite buffer overflow) limits the damage even if exploited.

Exploit ScenarioDerived

A local user with high-privilege (such as a domain administrator or system operator in a corporate virtualized environment) on a RHEL guest system invokes a crafted sequence of virtio device unmap operations with an artificially inflated descriptor count that exceeds the RhelDoUnMap() function's internal buffer allocation. This triggers a buffer overrun that crashes the driver or kernel subsystem, rendering the guest operating system unavailable. No public exploit code has been identified, and active exploitation is not confirmed; the attack requires direct local access and high privilege, limiting opportunistic exploitation.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 30, 2026

Buffer overflow in virtio-win's RhelDoUnMap() function allows local privileged users to trigger a denial of service by supplying an excessive number of descriptors during unmap operations, causing system crashes. Affects Red Hat Enterprise Linux 8, 9, and 10 across multiple architectures. The vulnerability requires high-level privilege (PR:H) but offers no confidentiality or integrity protections beyond the immediate DoS impact, with a CVSS score of 6.7 reflecting the local attack requirement and high-privilege barrier.

RemediationAI

Obtain and install the patched version of virtio-win released by Red Hat for RHEL 8, 9, and 10 as detailed in the official security advisory at https://access.redhat.com/security/cve/CVE-2026-5164. The upstream fix is available in GitHub PR #1504 at https://github.com/virtio-win/kvm-guest-drivers-windows/pull/1504; confirm that your RHEL distribution includes the corresponding patched driver version before deployment. As an interim mitigation, restrict high-privilege user account access on virtualized systems and monitor for unmap request anomalies in virtio-win driver logs. Apply the patch during the next scheduled maintenance window, as the local attack requirement and privilege barrier provide some time for planning.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Virtio-win is a Windows guest driver package for KVM/QEMU virtualization environments that implements paravirtualized I/O devices using the Virtio protocol. The RhelDoUnMap() function is responsible for handling descriptor unmapping requests, which are part of the Virtio device communication protocol. The vulnerability stems from insufficient bounds checking (CWE-120: Buffer Copy without Checking Size of Input) on user-supplied descriptor counts, allowing an attacker to write beyond allocated buffer boundaries. The affected CPE identifiers indicate this impacts RHEL systems running virtio-win drivers across versions 8, 9, and 10.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.7 MEDIUM
AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Red Hat 6.7 MEDIUM

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

A flaw was found in virtio-win. The RhelDoUnMap() function does not properly validate the number of descriptors provided by a user during an unmap request. A local user could exploit this input validation vulnerability by supplying an excessive number of descriptors, leading to a buffer overrun. This can cause a system crash, resulting in a Denial of Service (DoS).

Threat Intelligence Overview

EPSS Score
0.0%
Top 99% exploitable
Data Quality
7 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment Vendor GitHub

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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.0%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

34
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +34
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)CVE.org

cpe:2.3:a:red_hat:red_hat_enterprise_linux_10:*:*:*:*:*:*:*:*
cpe:2.3:a:red_hat:red_hat_enterprise_linux_8:*:*:*:*:*:*:*:*
cpe:2.3:a:red_hat:red_hat_enterprise_linux_9:*:*:*:*:*:*:*:*

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