CVE-2026-5164

Guest crash via unchecked unmap descriptor count

Published Mar 30, 2026 · Updated Mar 30, 2026

Buffer overflow in virtio-win on Red Hat Enterprise Linux 9 and 10 allows local users in Windows guests to crash the guest via an unmap request. RhelDoUnMap() copies a user-supplied BlockDescrCount into a 16-entry blk_discard array without checking the count or minimum buffer length. A user able to submit storage unmap operations inside an affected Windows guest can overrun the array and trigger an immediate system crash.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in virtio-win on Red Hat Enterprise Linux 9 and 10 allows local users in Windows guests to crash the guest via an unmap request. RhelDoUnMap() copies a user-supplied BlockDescrCount into a 16-entry blk_discard array without checking the count or minimum buffer length. A user able to submit storage unmap operations inside an affected Windows guest can overrun the array and trigger an immediate system crash.

The record

CVE
CVE-2026-5164
Published
Mar 30, 2026
Updated
Mar 30, 2026
Vendor
389 Directory Server
Product
Red Hat Enterprise Linux 10
Classifications
CWE-120, T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Mar 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 30, 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?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

389 Directory Server · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

Published CVSS scores

6.7Red HatCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application or System Exploitation

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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